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Koyama Y, Suico MA, Owaki A, Sato R, Kuwazuru J, Kaseda S, Sannomiya Y, Horizono J, Omachi K, Horinouchi T, Yamamura T, Tsuhako H, Nozu K, Shuto T, Kai H. Trimerization profile of type IV collagen COL4A5 exon deletion in X-linked Alport syndrome. Clin Exp Nephrol 2024; 28:874-881. [PMID: 38658441 DOI: 10.1007/s10157-024-02503-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 04/01/2024] [Indexed: 04/26/2024]
Abstract
BACKGROUND Alport syndrome (AS) is a genetic kidney disease caused by a mutation in type IV collagen α3, α4, and α5, which are normally secreted as heterotrimer α345(IV). Nonsense mutation in these genes causes severe AS phenotype. We previously revealed that the exon-skipping approach to remove a nonsense mutation in α5(IV) ameliorated the AS pathology. However, the effect of removing an exon on trimerization is unknown. Here, we assessed the impact of exon deletion on trimerization to evaluate their possible therapeutic applicability and to predict the severity of mutations associated with exon-skipping. METHODS We produced exon deletion constructs (ΔExon), nonsense, and missense mutants by mutagenesis and evaluated their trimer formation and secretion activities using a nanoluciferase-based assay that we previously developed. RESULTS Exon-skipping had differential effects on the trimer secretion of α345(IV). Some ΔExons could form and secrete α345(IV) trimers and had higher activity compared with nonsense mutants. Other ΔExons had low secretion activity, especially for those with exon deletion near the C-terminal end although the intracellular trimerization was normal. No difference was noted in the secretion of missense mutants and their ΔExon counterpart. CONCLUSION Exon skipping is advantageous for nonsense mutants in AS with severe phenotypes and early onset of renal failure but applications may be limited to ΔExons capable of normal trimerization and secretion. This study provides information on α5(IV) exon-skipping for possible therapeutic application and the prediction of the trimer behavior associated with exon-skipping in Alport syndrome.
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Affiliation(s)
- Yuimi Koyama
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City, 862-0973, Japan
| | - Mary Ann Suico
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City, 862-0973, Japan
- Global Center for Natural Resources Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Aimi Owaki
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City, 862-0973, Japan
| | - Ryoichi Sato
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City, 862-0973, Japan
| | - Jun Kuwazuru
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City, 862-0973, Japan
| | - Shota Kaseda
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City, 862-0973, Japan
| | - Yuya Sannomiya
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City, 862-0973, Japan
| | - Jun Horizono
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City, 862-0973, Japan
| | - Kohei Omachi
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City, 862-0973, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Haruki Tsuhako
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City, 862-0973, Japan
| | - Kandai Nozu
- Department of Pediatrics, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Tsuyoshi Shuto
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City, 862-0973, Japan.
- Global Center for Natural Resources Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
| | - Hirofumi Kai
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City, 862-0973, Japan.
- Global Center for Natural Resources Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
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Puapatanakul P, Miner JH. Alport syndrome and Alport kidney diseases - elucidating the disease spectrum. Curr Opin Nephrol Hypertens 2024; 33:283-290. [PMID: 38477333 PMCID: PMC10990029 DOI: 10.1097/mnh.0000000000000983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
PURPOSE OF REVIEW With the latest classification, variants in three collagen IV genes, COL4A3 , COL4A4 , and COL4A5 , represent the most prevalent genetic kidney disease in humans, exhibiting diverse, complex, and inconsistent clinical manifestations. This review breaks down the disease spectrum and genotype-phenotype correlations of kidney diseases linked to genetic variants in these genes and distinguishes "classic" Alport syndrome (AS) from the less severe nonsyndromic genetically related nephropathies that we suggest be called "Alport kidney diseases". RECENT FINDINGS Several research studies have focused on the genotype-phenotype correlation under the latest classification scheme of AS. The historic diagnoses of "benign familial hematuria" and "thin basement membrane nephropathy" linked to heterozygous variants in COL4A3 or COL4A4 are suggested to be obsolete, but instead classified as autosomal AS by recent expert consensus due to a significant risk of disease progression. SUMMARY The concept of Alport kidney disease extends beyond classic AS. Patients carrying pathogenic variants in any one of the COL4A3/A4/A5 genes can have variable phenotypes ranging from completely normal/clinically unrecognizable, hematuria without or with proteinuria, or progression to chronic kidney disease and kidney failure, depending on sex, genotype, and interplays of other genetic as well as environmental factors.
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Affiliation(s)
- Pongpratch Puapatanakul
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Nephrology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Jeffrey H. Miner
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
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Bergeron NAD, Garneau AP, Rousseau-Gagnon M, Riopel J, Isenring P. X-linked Alport syndrome presenting in mother and son with the same unique histopathological features. J Nephrol 2024; 37:769-772. [PMID: 38668984 PMCID: PMC11150303 DOI: 10.1007/s40620-024-01942-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 03/24/2024] [Indexed: 06/05/2024]
Abstract
Alport syndrome has been linked to three different genes, that is, COL4A3, COL4A4 and COL4A5. It is characterized by progressive and non-specific glomerulosclerosis with irregular thickening of the glomerular basement membrane (GBM). At times, the histopathologic picture is dominated by lesions that are consistent with focal and segmental glomerulosclerosis or IgA nephropathy. Here, we report the cases of two related individuals (mother and son) who were diagnosed with COL4A5-related Alport syndrome due to a missense variant (p.Gly1170Ser) in a G-X-Y repeat and found to present the same highly unusual histopathological abnormalities on their kidney biopsies. One of the abnormalities shared, which does not appear to have been reported, was reduced COL4A5 immunolabeling that was limited to Bowman's capsule even though the ultrastructure of the GBM was distorted. The other abnormality was superimposed segmental IgA deposition in both individuals, accompanied by mesangial changes in the mother. We feel that these findings provide novel insight into the mechanisms of disease manifestation in Alport syndrome. They suggest, in particular, that collagen expression and/or assemblies in Bowman's capsule is more vulnerable to missense mutations in COL4A5 than elsewhere in the kidney. Our findings also suggest that certain coinherited gene polymorphisms act as unexpectedly important phenotypic determinants in COL4A-related disorders.
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Affiliation(s)
- Nicolas A D Bergeron
- Service of Nephrology, L'Hôtel-Dieu de Québec Research Center, CHU de Québec-Université Laval, 10 McMahon Street (Room 3852), Québec, QC, G1R 2J6, Canada
| | - Alexandre P Garneau
- Service de Néphrologie-Transplantation Rénale Adultes, Hôpital Necker-Enfants Malades, AP-HP, Inserm U1151, Université Paris Cité, Rue de Sèvres, Paris, France
| | - Mathieu Rousseau-Gagnon
- Service of Nephrology, L'Hôtel-Dieu de Québec Research Center, CHU de Québec-Université Laval, 10 McMahon Street (Room 3852), Québec, QC, G1R 2J6, Canada
| | - Julie Riopel
- Service of Pathology, CHU de Québec-Université Laval, Québec, QC, G1R 2J6, Canada
| | - Paul Isenring
- Service of Nephrology, L'Hôtel-Dieu de Québec Research Center, CHU de Québec-Université Laval, 10 McMahon Street (Room 3852), Québec, QC, G1R 2J6, Canada.
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Kalmár T, Turkevi-Nagy S, Bitó L, Kaiser L, Maróti Z, Jakab D, Letoha A, Légrády P, Iványi B. Phenotype-Genotype Correlations in Three Different Cases of Adult-Onset Genetic Focal Segmental Glomerulosclerosis. Int J Mol Sci 2023; 24:17489. [PMID: 38139322 PMCID: PMC10743622 DOI: 10.3390/ijms242417489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/08/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
This study highlights the importance of a combined diagnostic approach in the diagnosis of rare diseases, such as adult-onset genetic FSGS. We present three adult patient cases evaluated with kidney biopsy for proteinuria, chronic kidney disease, and hypertension, which were suggestive of adult-onset genetic FSGS. Renal biopsy samples and formalin-fixed, paraffin-embedded fetal kidneys were evaluated using standard light microscopical stainings, direct immunofluorescence on cryostat sections, and electron microscopy. Clinical exome sequencing was performed for each case, and 45 FSGS-related genes were analyzed. Identifying mutations in the PAX2, ACTN4, and COL4A5 genes have prompted a re-evaluation of the previous histopathological examinations. The PAX2 mutation led to a thinner nephrogenic zone and decreased number of glomeruli, resulting in oligohydramnios during fetal development and oligomeganephronia and adaptive focal-segmental glomerulosclerosis in adulthood. The ACTN4 mutation caused distinct electron-dense aggregates in podocyte cell bodies, while the COL4A5 mutation led to segmental sclerosis of glomeruli with marked interstitial fibrosis and tubular atrophy. The identification of specific mutations and their histopathological consequences can lead to a better understanding of the disease and its progression, as well as potential treatment options.
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Affiliation(s)
- Tibor Kalmár
- Department of Pediatrics, Albert Szent-Györgyi Health Centre, University of Szeged, Temesvari krt 35-37, 6726 Szeged, Hungary (Z.M.)
| | - Sándor Turkevi-Nagy
- Department of Pediatrics, Albert Szent-Györgyi Health Centre, University of Szeged, Temesvari krt 35-37, 6726 Szeged, Hungary (Z.M.)
| | - László Bitó
- Department of Internal Medicine, Albert Szent-Györgyi Health Centre, University of Szeged, 6726 Szeged, Hungary
| | - László Kaiser
- Department of Pediatrics, Albert Szent-Györgyi Health Centre, University of Szeged, Temesvari krt 35-37, 6726 Szeged, Hungary (Z.M.)
| | - Zoltán Maróti
- Department of Pediatrics, Albert Szent-Györgyi Health Centre, University of Szeged, Temesvari krt 35-37, 6726 Szeged, Hungary (Z.M.)
| | - Dániel Jakab
- Department of Pediatrics, Albert Szent-Györgyi Health Centre, University of Szeged, Temesvari krt 35-37, 6726 Szeged, Hungary (Z.M.)
| | - Annamária Letoha
- Department of Internal Medicine, Centre of Clinical Infectology and Acute Internal Medicine, Albert Szent-Györgyi Health Centre, University of Szeged, 6726 Szeged, Hungary
| | - Péter Légrády
- Department of Internal Medicine, Albert Szent-Györgyi Health Centre, University of Szeged, 6726 Szeged, Hungary
| | - Béla Iványi
- Department of Pediatrics, Albert Szent-Györgyi Health Centre, University of Szeged, Temesvari krt 35-37, 6726 Szeged, Hungary (Z.M.)
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Di H, Wang Q, Liang D, Zhang J, Gao E, Zheng C, Yu X, Liu Z. Genetic features and kidney morphological changes in women with X-linked Alport syndrome. J Med Genet 2023; 60:1169-1176. [PMID: 37225412 DOI: 10.1136/jmg-2023-109221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 05/10/2023] [Indexed: 05/26/2023]
Abstract
BACKGROUND X-linked Alport syndrome (XLAS) caused by COL4A5 pathogenic variants usually has heterogeneous phenotypes in female patients. The genetic characteristics and glomerular basement membrane (GBM) morphological changes in women with XLAS need to been further investigated. METHODS A total of 83 women and 187 men with causative COL4A5 variants were enrolled for comparative analysis. RESULTS Women were more frequently carrying de novo COL4A5 variants compared with men (47% vs 8%, p=0.001). The clinical manifestations in women were variable, and no genotype-phenotype correlation was observed. Coinherited podocyte-related genes, including TRPC6, TBC1D8B, INF2 and MYH9, were identified in two women and five men, and the modifying effects of coinherited genes contributed to the heterogeneous phenotypes in these patients. X-chromosome inactivation (XCI) analysis of 16 women showed that 25% were skewed XCI. One patient preferentially expressing the mutant COL4A5 gene developed moderate proteinuria, and two patients preferentially expressing the wild-type COL4A5 gene presented with haematuria only. GBM ultrastructural evaluation demonstrated that the degree of GBM lesions was associated with the decline in kidney function for both genders, but more severe GBM changes were found in men compared with women. CONCLUSIONS The high frequency of de novo variants carried by women indicates that the lack of family history tends to make them susceptible to be underdiagnosed. Coinherited podocyte-related genes are potential contributors to the heterogeneous phenotype of some women. Furthermore, the association between the degree of GBM lesions and decline in kidney function is valuable in evaluating the prognosis for patients with XLAS.
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Affiliation(s)
- Hongling Di
- National Clinical Research Center of Kidney Diseases, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
| | - Qing Wang
- National Clinical Research Center of Kidney Diseases, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
- Department of Nephrology, General Hospital of Eastern Theater Command, Naval Medical University, Shanghai, Shanghai, China
| | - Dandan Liang
- National Clinical Research Center of Kidney Diseases, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
| | - Jiahui Zhang
- The Key Laboratory of Biosystems Homeostasis & Protection of Ministry of Education, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang, China
| | - Erzhi Gao
- National Clinical Research Center of Kidney Diseases, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
| | - Chunxia Zheng
- National Clinical Research Center of Kidney Diseases, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
| | - Xiaomin Yu
- Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, Zhejiang, China
| | - Zhihong Liu
- National Clinical Research Center of Kidney Diseases, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
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Hirayama R, Toyohara K, Watanabe K, Otsuki T, Araoka T, Mae SI, Horinouchi T, Yamamura T, Okita K, Hotta A, Iijima K, Nozu K, Osafune K. iPSC-derived type IV collagen α5-expressing kidney organoids model Alport syndrome. Commun Biol 2023; 6:854. [PMID: 37770589 PMCID: PMC10539496 DOI: 10.1038/s42003-023-05203-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 08/02/2023] [Indexed: 09/30/2023] Open
Abstract
Alport syndrome (AS) is a hereditary glomerulonephritis caused by COL4A3, COL4A4 or COL4A5 gene mutations and characterized by abnormalities of glomerular basement membranes (GBMs). Due to a lack of curative treatments, the condition proceeds to end-stage renal disease even in adolescents. Hampering drug discovery is the absence of effective in vitro methods for testing the restoration of normal GBMs. Here, we aimed to develop kidney organoid models from AS patient iPSCs for this purpose. We established iPSC-derived collagen α5(IV)-expressing kidney organoids and confirmed that kidney organoids from COL4A5 mutation-corrected iPSCs restore collagen α5(IV) protein expression. Importantly, our model recapitulates the differences in collagen composition between iPSC-derived kidney organoids from mild and severe AS cases. Furthermore, we demonstrate that a chemical chaperone, 4-phenyl butyric acid, has the potential to correct GBM abnormalities in kidney organoids showing mild AS phenotypes. This iPSC-derived kidney organoid model will contribute to drug discovery for AS.
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Affiliation(s)
- Ryuichiro Hirayama
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan
- Taisho Pharmaceutical Co., Ltd., Saitama, 331-9530, Japan
| | - Kosuke Toyohara
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan
| | - Kei Watanabe
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan
| | - Takeya Otsuki
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan
| | - Toshikazu Araoka
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan
| | - Shin-Ichi Mae
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Hyogo, 650-0017, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Hyogo, 650-0017, Japan
| | - Keisuke Okita
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan
| | - Akitsu Hotta
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Hyogo, 650-0017, Japan
- Hyogo Prefectural Kobe Children's Hospital, Hyogo, 650-0047, Japan
- Department of Advanced Pediatric Medicine, Kobe University Graduate School of Medicine, Hyogo, 650-0017, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Hyogo, 650-0017, Japan
| | - Kenji Osafune
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, 606-8507, Japan.
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Liang L, Wu H, Cai Z, Zhao J. Genetic and molecular dynamics analysis of two variants of the COL4A5 gene causing Alport syndrome. BMC Med Genomics 2023; 16:192. [PMID: 37596645 PMCID: PMC10436629 DOI: 10.1186/s12920-023-01623-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 07/31/2023] [Indexed: 08/20/2023] Open
Abstract
BACKGROUND Alport syndrome (AS; OMIM#308,940) is a hereditary kidney disease that progresses over time and is distinguished by hearing loss and ocular irregularities. The syndrome has three subtypes, namely X-linked (XL; OMIM#301,050), autosomal recessive (AR; OMIM#203,780), and autosomal dominant (AD; OMIM#104,200), which are categorized based on their respective modes of inheritance. XLAS is attributed to a pathogenic variant in the COL4A5 (OMIM*303,630) gene, which encodes the α5(IV) chain of type IV collagen (Col-IV). In contrast, ADAS and ARAS are the result of variants in the COL4A3 (OMIM*120,070) and COL4A4 (OMIM*120,131) genes, which encode the α3(IV) and α4(IV) chains of Col-IV, respectively. Typically, the diagnosis of AS necessitates hereditary or pathological assessments. The determination of splicing variants as pathogenic or non-pathogenic based on gene sequencing outcomes is challenging. METHODS In this study, we conducted exome sequencing and Sanger sequencing on two unrelated Chinese patients with AS. We identified a deletion variant c.4414delG in the COL4A5 gene and a splicing variant c.4298-20T > A in the same gene. In order to ascertain the impact of c.4298-20T > A on the synthesis of COL4A5 mRNA, we performed experiments involving minigene splicing. Additionally, we predicted the ability of these two variants to affect triple helix formation of α345(IV) using molecular dynamics methods. RESULTS The c.4414delG deletion variant caused a change in the genetic code of the COL4A5 gene. Specifically, it caused a shift in codon 1472 from encoding aspartate to encoding methionine. This shift resulted in a change of 75 amino acids in the protein sequence, ultimately leading to an early stop codon. This premature stop codon caused the production of a truncated α5(IV) chain with a predicted protein effect of p.D1472Mfs. The mRNA of the COL4A5 gene experienced intron 46 retention due to the splicing variant c.4298-20T > A, leading to the inclusion of six additional amino acids between amino acids 1432 and 1433 of the α5(IV) chain. This variant is predicted to have a protein effect of p.(P1432_G1433insDYFVEI). The impact of two variants, c.4414delG and c.4298-20T > A, on the aggregation region for α3(IV), α4(IV), and α5(IV) trimerisation were studied using molecular dynamics simulations. Results showed that the deletion variant c.4414delG had a significantly stronger disruption on NC1, compared to the splicing variant c.4298-20T > A. This difference in impact is consistent with the varying clinical phenotypes observed in the two patients. Based on the American College of Medical Genetics and Genomics (ACMG) classification criteria and guidelines for genetic variants, the deletion variant c.4414delG was rated as pathogenic while the splicing variant c.4298-20T > A was rated as likely-pathogenic. CONCLUSION Our study has identified two novel pathogenic loci, the deletion variant c.4414delG and the splicing variant c.4298-20T > A, associated with XLAS. This finding expands the genetic spectrum of XLAS. We suggest that molecular dynamics can effectively model the effect of genetic variation on α345(IV) trimerization, which may offer valuable insights into the mechanisms of XLAS pathogenesis.
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Affiliation(s)
- Lei Liang
- Center for Prenatal Diagnosis and Medical Genetics, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, 010015, PR China
| | - Haotian Wu
- School of Public Health, Inner Mongolia Medical University, Hohhot, 010015, PR China
| | - Zeyu Cai
- Department of Nephrology, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, 010015, PR China
| | - Jianrong Zhao
- Department of Nephrology, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, 010015, PR China.
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Kuwazuru J, Suico MA, Omachi K, Kojima H, Kamura M, Kaseda S, Kawahara T, Hitora Y, Kato H, Tsukamoto S, Wada M, Asano T, Kotani S, Nakajima M, Misumi S, Sannomiya Y, Horizono J, Koyama Y, Owaki A, Shuto T, Kai H. CyclosporinA Derivative as Therapeutic Candidate for Alport Syndrome by Inducing Mutant Type IV Collagen Secretion. KIDNEY360 2023; 4:909-917. [PMID: 37143203 PMCID: PMC10371266 DOI: 10.34067/kid.0000000000000134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 04/04/2023] [Indexed: 05/06/2023]
Abstract
Key Points Screening of natural product extracts to find candidate compounds that increase mutant type IV collagen α 3,4,5 (α 345(IV)) trimer secretion in Alport syndrome (AS). Cyclosporin A (CsA) and alisporivir (ALV) increase mutant α 345(IV) trimer secretion in AS. PPIF/cyclophilin D mediates the effect of CsA and ALV on mutant trimer secretion. Background Type IV collagen α 3,4,5 (α 345(IV)) is an obligate trimer that is secreted to form a collagen network, which is the structural foundation of basement membrane. Mutation in one of the genes (COL4A3 , A4 , A5 ) encoding these proteins underlies the progressive genetic nephropathy Alport syndrome (AS) due to deficiency in trimerization and/or secretion of the α 345(IV) trimer. Thus, improving mutant α 345(IV) trimerization and secretion could be a good therapeutic approach for AS. Methods Using the nanoluciferase-based platform that we previously developed to detect α 345(IV) formation and secretion in HEK293T cells, we screened libraries of natural product extracts and compounds to find a candidate compound capable of increasing mutant α 345(IV) secretion. Results The screening of >13,000 extracts and >600 compounds revealed that cyclosporin A (CsA) increased the secretion of mutant α 345(IV)-G1244D. To elucidate the mechanism of the effect of CsA, we evaluated CsA derivatives with different ability to bind to calcineurin (Cn) and cyclophilin (Cyp). Alisporivir (ALV), which binds to Cyp but not to Cn, increased the trimer secretion of mutant α 345(IV). Knockdown studies on Cyps showed that PPIF/cyclophilin D was involved in the trimer secretion-enhancing activity of CsA and ALV. We confirmed that other α 345(IV) mutants are also responsive to CsA and ALV. Conclusions CsA was previously reported to improve proteinuria in patients with AS, but owing to its nephrotoxic effect, CsA is not recommended for treatment in patients with AS. Our data raise the possibility that ALV could be a safer option than CsA. This study provides a novel therapeutic candidate for AS with an innovative mechanism of action and reveals an aspect of the intracellular regulatory mechanism of α 345(IV) that was previously unexplored.
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Affiliation(s)
- Jun Kuwazuru
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Mary Ann Suico
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
- Global Center for Natural Resources Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Kohei Omachi
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Haruka Kojima
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Misato Kamura
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Shota Kaseda
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Teppei Kawahara
- Department of Instrumental Analysis, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
- Useful and Unique Natural Products for Drug Discovery and Development (UpRod), Program for Building Regional Innovation Ecosystems, Kumamoto University, Kumamoto, Japan
| | - Yuki Hitora
- Global Center for Natural Resources Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
- Department of Natural Medicines, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Hikaru Kato
- Global Center for Natural Resources Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
- Department of Natural Medicines, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Sachiko Tsukamoto
- Global Center for Natural Resources Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
- Department of Natural Medicines, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Mikiyo Wada
- Department of Instrumental Analysis, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
- Useful and Unique Natural Products for Drug Discovery and Development (UpRod), Program for Building Regional Innovation Ecosystems, Kumamoto University, Kumamoto, Japan
| | - Toshifumi Asano
- Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Shunsuke Kotani
- Global Center for Natural Resources Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
- Department of Instrumental Analysis, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Makoto Nakajima
- Department of Organic Chemistry, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Shogo Misumi
- Global Center for Natural Resources Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
- Department of Environmental and Molecular Health Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Yuya Sannomiya
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Jun Horizono
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Yuimi Koyama
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Aimi Owaki
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Tsuyoshi Shuto
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
- Global Center for Natural Resources Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Hirofumi Kai
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
- Global Center for Natural Resources Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
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9
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Kim JH, Lim SH, Song JY, Cho MH, Hyun H, Yang EM, Lee JW, Cho MH, Park MJ, Lee JH, Jung J, Yoo KH, Jang KM, Pai KS, Suh JS, Namgoong MK, Chung WY, Kim SJ, Cho EY, Kim KM, Kim NH, Kim M, Paik JH, Kang HG, Ahn YH, Cheong HI. Genotype-phenotype correlation of X-linked Alport syndrome observed in both genders: a multicenter study in South Korea. Sci Rep 2023; 13:6827. [PMID: 37100867 PMCID: PMC10133262 DOI: 10.1038/s41598-023-34053-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 04/24/2023] [Indexed: 04/28/2023] Open
Abstract
The genotype-phenotype correlation of the X-linked Alport syndrome (XLAS) has been well elucidated in males, whereas it remains unclear in females. In this multicenter retrospective study, we analyzed the genotype-phenotype correlation in 216 Korean patients (male:female = 130:86) with XLAS between 2000 and 2021. The patients were divided into three groups according to their genotypes: the non-truncating group, the abnormal splicing group, and the truncating group. In male patients, approximately 60% developed kidney failure at the median age of 25.0 years, and kidney survival showed significant differences between the non-truncating and truncating groups (P < 0.001, hazard ratio (HR) 2.8) and splicing and truncating groups (P = 0.002, HR 3.1). Sensorineural hearing loss was detected in 65.1% of male patients, while hearing survival periods showed a highly significant difference between the non-truncating and truncating groups (P < 0.001, HR 5.1). In female patients, approximately 20% developed kidney failure at the median age of 50.2 years. The kidney survival was significantly different between the non-truncating and truncating groups (P = 0.006, HR 5.7). Our findings support the presence of genotype-phenotype correlation not only in male patients but also in female patients with XLAS.
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Affiliation(s)
- Ji Hyun Kim
- Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, South Korea
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, South Korea
| | - Seon Hee Lim
- Department of Pediatrics, Pusan National University Yangsan Children's Hospital and School of Medicine, Yangsan, South Korea
| | - Ji Yeon Song
- Department of Pediatrics, Pusan National University Yangsan Children's Hospital and School of Medicine, Yangsan, South Korea
| | - Myung Hyun Cho
- Department of Pediatrics, Hallym University Sacred Heart Hospital, Anyang, South Korea
| | - HyeSun Hyun
- Department of Pediatrics, College of Medicine, St. Vincent's Hospital, The Catholic University of Korea, Seoul, South Korea
| | - Eun Mi Yang
- Department of Pediatrics, Chonnam National University and School of Medicine, Gwangju, South Korea
| | - Jung Won Lee
- Department of Pediatrics, Ewha Womans University School of Medicine, Seoul, South Korea
| | - Min Hyun Cho
- Department of Pediatrics, Kyungpook National University, School of Medicine, Daegu, South Korea
| | - Min Ji Park
- Department of Pediatrics, Kyungpook National University, School of Medicine, Daegu, South Korea
| | - Joo Hoon Lee
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, South Korea
| | - Jiwon Jung
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, South Korea
| | - Kee Hwan Yoo
- Department of Nephrology, Woori Children's Hospital, Seoul, South Korea
| | - Kyung Mi Jang
- Department of Pediatrics, Yeungnam University College of Medicine, Gyeongsan, South Korea
| | - Ki Soo Pai
- Department of Pediatrics, Ajou University School of Medicine, Suwon, South Korea
| | - Jin-Soon Suh
- Department of Pediatrics, Bucheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Mee Kyung Namgoong
- Department of Pediatrics, Wonju Severance Christian Hospital, Yonsei University Wonju College of Medicine, Wonju, South Korea
| | | | - Su Jin Kim
- Department of Pediatrics, Inha University College of Medicine, Inha University Hospital, Incheon, South Korea
| | - Eun Young Cho
- Department of Pediatrics, Chungnam National University Hospital, Daejeon, South Korea
| | - Kyung Min Kim
- Department of Pediatrics, Chungnam National University Hospital, Daejeon, South Korea
| | - Nam Hee Kim
- Department of Pediatrics, Inje University Ilsan Paik Hospital, Goyang, South Korea
| | - Minsun Kim
- Department of Pediatrics, Jeonbuk National University Medical School, Jeonju, South Korea
| | - Jin Ho Paik
- Department of Pathology, Seoul National University Bundang Hospital and Seoul National University College of Medicine, Seongnam, South Korea
| | - Hee Gyung Kang
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, South Korea
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, South Korea
- Kidney Research Institute, Medical Research Center, Seoul National University, Seoul, South Korea
| | - Yo Han Ahn
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, South Korea.
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, South Korea.
- Kidney Research Institute, Medical Research Center, Seoul National University, Seoul, South Korea.
| | - Hae Il Cheong
- Department of Pediatrics, Seoul Red Cross Hospital, Seoul, South Korea.
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10
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Zacchia M, Capolongo G, Del Vecchio Blanco F, Secondulfo F, Gupta N, Blasio G, Pollastro RM, Cervesato A, Piluso G, Gigliotti G, Torella A, Nigro V, Perna AF, Capasso G, Trepiccione F. Next-Generation Sequencing (NGS) Analysis Illustrates the Phenotypic Variability of Collagen Type IV Nephropathies. Genes (Basel) 2023; 14:genes14030764. [PMID: 36981034 PMCID: PMC10048128 DOI: 10.3390/genes14030764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/13/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
Mutations in COL4A3-A5 cause a spectrum of glomerular disorders, including thin basement membrane nephropathy (TBMN) and Alport syndrome (AS). The wide application of next-generation sequencing (NGS) in the last few years has revealed that mutations in these genes are not limited to these clinical entities. In this study, 176 individuals with a clinical diagnosis of inherited kidney disorders underwent an NGS-based analysis to address the underlying cause; those who changed or perfected the clinical diagnosis after molecular analysis were selected. In 5 out of 83 individuals reaching a molecular diagnosis, the genetic result was unexpected: three individuals showed mutations in collagen type IV genes. These patients showed the following clinical pictures: (1) familial focal segmental glomerulosclerosis; (2) end-stage renal disease (ESRD) diagnosed incidentally in a 49-year-old man, with diffuse cortical calcifications on renal imaging; and (3) dysmorphic and asymmetric kidneys with multiple cysts and signs of tubule-interstitial defects. Genetic analysis revealed rare heterozygote/compound heterozygote COL4A4-A5 variants. Our study highlights the key role of NGS in the diagnosis of inherited renal disorders and shows the phenotype variability in patients carrying mutations in collagen type IV genes.
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Affiliation(s)
- Miriam Zacchia
- Department of Medical and Translational Sciences, University of Campania, Luigi Vanvitelli, 81100 Caserta, Italy
| | - Giovanna Capolongo
- Department of Medical and Translational Sciences, University of Campania, Luigi Vanvitelli, 81100 Caserta, Italy
| | | | - Floriana Secondulfo
- Department of Medical and Translational Sciences, University of Campania, Luigi Vanvitelli, 81100 Caserta, Italy
- Department of Precision Medicine, University of Campania, Luigi Vanvitelli, 81100 Caserta, Italy
| | - Neha Gupta
- Department of Medical and Translational Sciences, University of Campania, Luigi Vanvitelli, 81100 Caserta, Italy
- Biogem, Scarl, 83031 Ariano Irpino, Italy
| | - Giancarlo Blasio
- Department of Precision Medicine, University of Campania, Luigi Vanvitelli, 81100 Caserta, Italy
| | - Rosa Maria Pollastro
- Department of Medical and Translational Sciences, University of Campania, Luigi Vanvitelli, 81100 Caserta, Italy
| | - Angela Cervesato
- Department of Medical and Translational Sciences, University of Campania, Luigi Vanvitelli, 81100 Caserta, Italy
| | - Giulio Piluso
- Department of Precision Medicine, University of Campania, Luigi Vanvitelli, 81100 Caserta, Italy
| | - Giuseppe Gigliotti
- UOC Nefrologia e Dialisi, Ospedale Civile di Eboli "MM.SS. Addolorata", 84025 Eboli, Italy
| | - Annalaura Torella
- Department of Precision Medicine, University of Campania, Luigi Vanvitelli, 81100 Caserta, Italy
| | - Vincenzo Nigro
- Department of Precision Medicine, University of Campania, Luigi Vanvitelli, 81100 Caserta, Italy
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | - Alessandra F Perna
- Department of Medical and Translational Sciences, University of Campania, Luigi Vanvitelli, 81100 Caserta, Italy
| | | | - Francesco Trepiccione
- Department of Medical and Translational Sciences, University of Campania, Luigi Vanvitelli, 81100 Caserta, Italy
- Biogem, Scarl, 83031 Ariano Irpino, Italy
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11
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Liang L, Wu H, Cai Z, Zhao J. Molecular dynamics and minigene assay of new splicing variant c.4298-20T>A of COL4A5 gene that cause Alport syndrome. Front Genet 2023; 14:1059322. [PMID: 36923787 PMCID: PMC10009158 DOI: 10.3389/fgene.2023.1059322] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 02/13/2023] [Indexed: 03/02/2023] Open
Abstract
Introduction: Alport syndrome (AS; OMIM#308940) is a progressive hereditary kidney disease characterized by hearing loss and ocular abnormalities. According to the mode of inheritance, AS has three subtypes: X-linked (XL; OMIM#301050), autosomal recessive (AR; OMIM#203780), and autosomal dominant (AD; OMIM#104200). XLAS is caused by a pathogenic variant in COL4A5 (OMIM*303630) gene encoding type IV collagen (Col-IV) α5 chain, while ADAS and ARAS are consequences of a variant in COL4A3 (OMIM*120070) and COL4A4 (OMIM*120131) genes that encode Col-IV α3 and α4 chains, respectively. Usually, diagnosis of AS requires hereditary or pathological examinations. Splicing variants are hard to be determined as pathogenic or non-pathogenic based on the results of gene sequencing. Methods: This study focused on a splicing variant in COL4A5 gene, termed NM_000495.5: c.4298-20T>A, and to analyzed its authenticity and damaged α5 chain. In vitro minigene splicing assay was applied to investigate the effect of splicing variant, c.4298-20T>A, on COL4A5 mRNA synthesis. Molecular dynamics method was used to predict the capability of the responsible α5(IV) to form a triple helix. Results: The intron 46 of COL4A5 mRNA retained 18 bp, resulting in insertion of six amino acids behind the amino acid at position 1,433 of α5(IV). The predicted protein effect of this variant: p. (Pro1432_Gly1433insAspTyrPheValGluIle). As a consequence, the stability of α5(IV) secondary structure was impaired, probably leading to the unusual configuration of α345(IV). Discussion: Normally, splicing variant in COL4A5 gene can lead to phenotypes of XLAS, and the effect is associated with the extent of splicing. The patient reported here carried a c.4298-20T>A splicing variant in COL4A5 gene, and AS was highly suspected based on the pathology results. However, the patient did not manifest any ocular or ear abnormalities. We therefore present the c.4298-20T>A splicing variant in COL4A5 gene as likely-pathogenic splicing variant that leads to XLAS with mild phenotypes.
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Affiliation(s)
- Lei Liang
- Center for Prenatal Diagnosis and Medical Genetics, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, China
| | - Haotian Wu
- School of Public Health, Inner Mongolia Medical University, Hohhot, China
| | - Zeyu Cai
- Department of Nephrology, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, China
| | - Jianrong Zhao
- Department of Nephrology, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, China
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12
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Kohler J, Omachi K, Charu V, Miner JH, Bhalla V. A COL4A4-G394S Variant and Impaired Collagen IV Trimerization in a Patient with Mild Alport Syndrome. KIDNEY360 2022; 3:1899-1908. [PMID: 36514391 PMCID: PMC9717634 DOI: 10.34067/kid.0005472022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 10/18/2022] [Indexed: 04/14/2023]
Abstract
Background Missense variants in COL4A genes are often found in patients with an Alport syndrome-like presentation, but their pathogenicity is not always clear. We encountered a woman with microscopic hematuria and proteinuria at 33 years of age with a diagnosis of thin basement membrane disease who was approaching end stage kidney disease at 59 years of age. We hypothesized that this patient's kidney disease was within the spectrum of Alport syndrome. Methods We used histologic, genetic, and biochemical approaches to investigate the mechanisms of kidney disease. By immunofluorescence, we investigated collagen IV chain composition of the glomerular basement membrane (GBM). We employed targeted sequencing to search for pathogenic variants in COL4A and other relevant genes. We utilized N- and C-terminal split NanoLuciferase assays to determine the effect of a novel COL4A4 variant of uncertain significance (VUS) on collagen IV heterotrimer formation in vitro. We transfected COL4A4 expression constructs with split NanoLuciferase fragment-fused COL4A3 and COL4A5 constructs into human embryonic kidney 293T cells. To assay for α3α4α5(IV) heterotrimer formation and secretion, we measured luminescence in cell lysates and culture supernatants from transfected cells. Results Immunostaining suggested that the collagen α3α4α5(IV) network was present throughout the patient's GBMs. DNA sequencing revealed a novel homozygous VUS: COL4A4 c.1180G>A (p. Gly394Ser). In the C-terminal split luciferase-based α3α4α5(IV) heterotrimer formation assays, luminescence levels for G394S were comparable to WT, but in the N-terminal tag assays, the extracellular luminescence levels for G394S were decreased by approximately 50% compared with WT. Conclusions Our cell-based assay provides a platform to test COL4 VUS and shows that G394S impairs assembly of the α3α4α5(IV) N-terminus and subsequent trimer secretion. These data suggest that the COL4A4-G394S variant is pathogenic and causes an atypical mild form of autosomal recessive Alport syndrome.
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Affiliation(s)
- Jennefer Kohler
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Kohei Omachi
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Vivek Charu
- Department of Pathology, Stanford University School of Medicine, Stanford, California
| | - Jeffrey H. Miner
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Vivek Bhalla
- Division of Nephrology, Department of Medicine, Stanford School of Medicine, Stanford, California
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13
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Savige J, Huang M, Croos Dabrera MS, Shukla K, Gibson J. Genotype-Phenotype Correlations for Pathogenic COL4A3–COL4A5 Variants in X-Linked, Autosomal Recessive, and Autosomal Dominant Alport Syndrome. Front Med (Lausanne) 2022; 9:865034. [PMID: 35602506 PMCID: PMC9120524 DOI: 10.3389/fmed.2022.865034] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 03/24/2022] [Indexed: 12/28/2022] Open
Abstract
Alport syndrome is inherited as an X-linked (XL), autosomal recessive (AR), or autosomal dominant (AD) disease, where pathogenic COL4A3 – COL4A5 variants affect the basement membrane collagen IV α3α4α5 network. About 50% of pathogenic variants in each gene (major rearrangements and large deletions in 15%, truncating variants in 20%, splicing changes in 15%) are associated with “severe” disease with earlier onset kidney failure, and hearing loss and ocular abnormalities in males with XL inheritance and in males and females with AR disease. Severe variants are also associated with early proteinuria which is itself a risk factor for kidney failure. The other half of pathogenic variants are missense changes which are mainly Gly substitutions. These are generally associated with later onset kidney failure, hearing loss, and less often with major ocular abnormalities. Further determinants of severity for missense variants for XL disease in males, and in AD disease, include Gly versus non-Gly substitutions; increased distance from a non-collagenous interruption or terminus; and Gly substitutions with a more (Arg, Glu, Asp, Val, and Trp) or less disruptive (Ala, Ser, and Cys) residue. Understanding genotype-phenotype correlations in Alport syndrome is important because they help predict the likely age at kidney failure, and the need for early and aggressive management with renin-angiotensin system blockade and other therapies. Genotype-phenotype correlations also help standardize patients with Alport syndrome undergoing trials of clinical treatment. It is unclear whether severe variants predispose more often to kidney cysts or coincidental IgA glomerulonephritis which are recognized increasingly in COL4A3-, COL4A4 - and COL4A5-associated disease.
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14
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Sato M, Manabe S, Itabashi M, Horita S, Hirose O, Kawashima M, Nishida M, Kataoka H, Taneda S, Mochizuki T, Nitta K. Slowly Progressive Male Alport Syndrome Evaluated by Serial Biopsy: Importance of Type IV Collagen Staining. Intern Med 2022; 61:1205-1209. [PMID: 34645753 PMCID: PMC9107991 DOI: 10.2169/internalmedicine.7372-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 08/29/2021] [Indexed: 11/18/2022] Open
Abstract
A slowly progressive middle-aged man initially diagnosed with thin basement membrane nephropathy based on extensive thinning of the glomerular basement membrane (GBM) was subsequently diagnosed with Alport syndrome (AS) by a serial renal biopsy eight years later. The ultrastructural analysis of the second biopsy indicated thickening and wrinkling with mild reticulation in the GBM, consistent with AS. However, a retrospective analysis of the first biopsy revealed mild attenuation of type IV collagen α5 chain staining, suggesting a potential diagnosis of AS, despite the lack of ultrastructural features of AS. We herein report the clinical usefulness of type IV collagen staining in the early diagnosis of AS.
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Affiliation(s)
- Masayo Sato
- Department of Nephrology, Tokyo Women's Medical University, Japan
| | - Shun Manabe
- Department of Nephrology, Tokyo Women's Medical University, Japan
| | - Mitsuyo Itabashi
- Department of Nephrology, Tokyo Women's Medical University, Japan
| | - Shigeru Horita
- Department of Clinical Laboratory Medicine, Tokyo Women's Medical University Hospital, Japan
| | - Orie Hirose
- Department of Pathology, Tokyo Women's Medical University, Japan
| | - Moe Kawashima
- Department of Nephrology, Tokyo Women's Medical University, Japan
| | - Miki Nishida
- Department of Nephrology, Tokyo Women's Medical University, Japan
| | - Hiroshi Kataoka
- Department of Nephrology, Tokyo Women's Medical University, Japan
- Clinical Research Division for Polycystic Kidney Disease, Department of Medicine, Kidney Center, Tokyo Women's Medical University, Japan
| | - Sekiko Taneda
- Department of Pathology, Tokyo Women's Medical University, Japan
| | - Toshio Mochizuki
- Department of Nephrology, Tokyo Women's Medical University, Japan
- Clinical Research Division for Polycystic Kidney Disease, Department of Medicine, Kidney Center, Tokyo Women's Medical University, Japan
| | - Kosaku Nitta
- Department of Nephrology, Tokyo Women's Medical University, Japan
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15
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Wang S, Shao Y, Wang Y, Lu J, Shao L. Identification of Four Novel COL4A5 Variants and Detection of Splicing Abnormalities in Three Chinese X-Linked Alport Syndrome Families. Front Genet 2022; 13:847777. [PMID: 35368650 PMCID: PMC8968133 DOI: 10.3389/fgene.2022.847777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 03/01/2022] [Indexed: 12/03/2022] Open
Abstract
Chronic renal disease associated with X-linked Alport syndrome (XLAS) is relatively rare. However, due to the lack of specificity in the pathologic and clinical manifestations of the disease, it is easy to be misdiagnosed. In this study, we included three Chinese families with XLAS and used targeted NGS to find gene variants. In family X1, the 36-year-old male proband had hematuria, massive proteinuria, sensorineural deafness and ESRD at 33. In silico prediction showed the novel c.1424-4C > G variant reduced the score of the normal 3’ splice site from 0.47 to 0.00 (according to BDGP). Transcriptional analysis from his peripheral blood cells indicated that it caused the insertion of an amino acid [p.(Lys474_Gly475insVal)]. In family X2, the proband was a 32-year-old male, who had hematuria, proteinuria, hypertension, hearing loss and progressed into ESRD at 30 years. He carried a novel missense variant c.2777G > T p.(Gly926Val). In family X3, the proband, a 16-year-old male, had hematuria, massive proteinuria, sensorineural deafness and ESRD; the results of renal pathological findings were consistent with AS. He carried a novel variant c.4529-2A > T, so did his mother with ESRD and probable XLAS. Bioinformatic analysis with BDGP showed that it abolished the acceptor site from 0.83 to 0.00. RT-PCR analysis from his kidney tissue indicated that it caused exon 50 skipping and exon 50 skipping along with inserting a cryptic exon derived from intron 49 p.[Gly1510Aspfs*11, Gly1510Alafs*35]. Another novel missense variant c.1552G > A p.(Gly518Arg) was identified in his mother and his aunt. No skewed X-chromosome inactivation was involved in these two female patients. In conclusion, four novel variants in COL4A5 were identified and transcriptional analysis is essential to investigate the pathogenicity of intronic variants. Thus we found a rare event in a female patient with XLAS caused by two COL4A5 variants in trans.
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Affiliation(s)
- Sai Wang
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
- Department of Dermatology, Peking University First Hospital, Beijing, China
| | - Yingfei Shao
- Wenzhou Medical University Renji College, Wenzhou, China
| | - Yixiu Wang
- Darpartment of Hepatic Surgery, Shanghai Cancer Center, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jingru Lu
- School of Medicine, Southeast University, Nanjing, China
| | - Leping Shao
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
- *Correspondence: Leping Shao,
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16
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Oda Y, Sawa N, Nozu K, Ubara Y. Refractory focal segmental glomerulosclerosis caused by Alport syndrome detected by genetic testing after three decades. BMJ Case Rep 2022; 15:e247393. [PMID: 35288428 PMCID: PMC8921854 DOI: 10.1136/bcr-2021-247393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2022] [Indexed: 01/13/2023] Open
Abstract
A woman in her 50s with a three-decade history of biopsy-proven focal segmental glomerulosclerosis and a family history of end-stage kidney disease presented with worsening proteinuria and declining kidney function after three decades of immunosuppressive therapy. While a repeat kidney biopsy did not reveal findings diagnostic of Alport syndrome, genetic testing demonstrated a heterozygous mutation in COL4A5, which confirmed the diagnosis of X-linked Alport syndrome. The heterozygous in-frame deletion mutation may explain her intact hearing and relatively mild symptoms. Genetic testing enables diagnosis of Alport syndrome of various phenotypes, some of which cannot be diagnosed conventionally with clinical course and kidney biopsy. Genetic disorders including collagen IV nephropathy should be considered as a differential diagnosis in patients with focal segmental glomerulosclerosis, especially when a patient has early-onset proteinuria, a family history of kidney disease, syndromic features or proteinuria refractory to glucocorticoid treatment.
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Affiliation(s)
- Yasuhiro Oda
- Division of Nephrology and Endocrinology, The University of Tokyo Graduate School of Medicine, Tokyo, Japan
- Nephrology Center, Toranomon Hospital Kajigaya, Kawasaki, Japan
| | - Naoki Sawa
- Nephrology Center, Toranomon Hospital Kajigaya, Kawasaki, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yoshifumi Ubara
- Nephrology Center, Toranomon Hospital Kajigaya, Kawasaki, Japan
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17
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Gibson JT, Huang M, Shenelli Croos Dabrera M, Shukla K, Rothe H, Hilbert P, Deltas C, Storey H, Lipska-Ziętkiewicz BS, Chan MMY, Sadeghi-Alavijeh O, Gale DP, Cerkauskaite A, Savige J. Genotype-phenotype correlations for COL4A3-COL4A5 variants resulting in Gly substitutions in Alport syndrome. Sci Rep 2022; 12:2722. [PMID: 35177655 PMCID: PMC8854626 DOI: 10.1038/s41598-022-06525-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/24/2022] [Indexed: 12/21/2022] Open
Abstract
Alport syndrome is the commonest inherited kidney disease and nearly half the pathogenic variants in the COL4A3-COL4A5 genes that cause Alport syndrome result in Gly substitutions. This study examined the molecular characteristics of Gly substitutions that determine the severity of clinical features. Pathogenic COL4A5 variants affecting Gly in the Leiden Open Variation Database in males with X-linked Alport syndrome were correlated with age at kidney failure (n = 157) and hearing loss diagnosis (n = 80). Heterozygous pathogenic COL4A3 and COL4A4 variants affecting Gly (n = 304) in autosomal dominant Alport syndrome were correlated with the risk of haematuria in the UK 100,000 Genomes Project. Gly substitutions were stratified by exon location (1 to 20 or 21 to carboxyl terminus), being adjacent to a non-collagenous region (interruption or terminus), and the degree of instability caused by the replacement residue. Pathogenic COL4A5 variants that resulted in a Gly substitution with a highly destabilising residue reduced the median age at kidney failure by 7 years (p = 0.002), and age at hearing loss diagnosis by 21 years (p = 0.004). Substitutions adjacent to a non-collagenous region delayed kidney failure by 19 years (p = 0.014). Heterozygous pathogenic COL4A3 and COL4A4 variants that resulted in a Gly substitution with a highly destabilising residue (Arg, Val, Glu, Asp, Trp) were associated with an increased risk of haematuria (p = 0.018), and those adjacent to a non-collagenous region were associated with a reduced risk (p = 0.046). Exon location had no effect. In addition, COL4A5 variants adjacent to non-collagenous regions were over-represented in the normal population in gnomAD (p < 0.001). The nature of the substitution and of nearby residues determine the risk of haematuria, early onset kidney failure and hearing loss for Gly substitutions in X-linked and autosomal dominant Alport syndrome.
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Affiliation(s)
- Joel T Gibson
- Department of Medicine (Melbourne Health and Northern Health), Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Mary Huang
- Department of Medicine (Melbourne Health and Northern Health), Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Marina Shenelli Croos Dabrera
- Department of Medicine (Melbourne Health and Northern Health), Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Krushnam Shukla
- Department of Medicine (Melbourne Health and Northern Health), Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Hansjörg Rothe
- Centre for Nephrology and Metabolic Disorders, 02943, Weisswasser, Germany
| | - Pascale Hilbert
- Departement de Biologie Moleculaire, Institute de Pathologie et de Genetique ASBL, Gosselies, Belgium
| | - Constantinos Deltas
- Center of Excellence in Biobanking and Biomedical Research, University of Cyprus Medical School, Nicosia, Cyprus
| | - Helen Storey
- Molecular Genetics, Viapath Laboratories, 5th Floor Tower Wing, Guy's Hospital, London, SE1 9RT, UK
| | | | - Melanie M Y Chan
- Department of Renal Medicine, University College London, London, UK
| | | | - Daniel P Gale
- Department of Renal Medicine, University College London, London, UK
| | - Agne Cerkauskaite
- Institute of Biomedical Sciences, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Judy Savige
- Department of Medicine (Melbourne Health and Northern Health), Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia.
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Chen X, Ye N, Zhang L, Zheng W, Cheng J, Gong M. Functional assessment of a novel COL4A5 splicing site variant in a Chinese X-linked Alport syndrome family. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:1420. [PMID: 34733972 PMCID: PMC8506736 DOI: 10.21037/atm-21-3523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 09/03/2021] [Indexed: 02/05/2023]
Abstract
Background Chronic kidney disease caused by X-linked Alport syndrome (XLAS) is relatively rare. However, due to the nonspecific pathologic and clinical manifestations of this disease, it is easily misdiagnosed. Genetic testing is crucial in identifying suspected cases. In addition, the results of genetic testing are an important indicator of patient prognosis. This study demonstrated a novel pathogenic COL4A5 splicing site variant in a Chinese family with XLAS. Methods Targeted next generation sequencing (NGS) was performed to identify the gene variant in the family members, and the gene mutation site was confirmed by Sanger sequencing. We then further analyzed the consequences of this gene mutation on the translated protein of this variant using in silico and in vitro approaches. Results A novel splice region variant, c.1033-2(IVS 18) A>G, in COL4A5 intron 18 was identified in the affected family members. Sanger sequencing confirmed that this variant is segregated with disease. In silico analysis, this variant led to frame-shift and premature termination on the translation of the nucleic acid, and this result was verified by RNA splicing analysis in a cell model. Unexpectedly, we still observed positive immunohistology staining of collagen IV α5 in the glomerular basement membrane (GBM) of the index patient, which implied that another potential transcription or translation mechanism skipping the mutated site might exist. Conclusions Our present finding expands the mutational spectrum for the COL4A5 gene associated with XLAS and highlights the genotype-phenotype correlations in this disease.
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Affiliation(s)
- Xiaolei Chen
- Department of Nephrology, West China Hospital, Sichuan University, Chengdu, China
| | - Nan Ye
- Laboratory of Proteomics and Metabolomics for Diseases, Institutes for Systems Genetics, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Lu Zhang
- Laboratory of Proteomics and Metabolomics for Diseases, Institutes for Systems Genetics, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Wen Zheng
- Laboratory of Proteomics and Metabolomics for Diseases, Institutes for Systems Genetics, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Jingqiu Cheng
- Laboratory of Proteomics and Metabolomics for Diseases, Institutes for Systems Genetics, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
| | - Meng Gong
- Laboratory of Proteomics and Metabolomics for Diseases, Institutes for Systems Genetics, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, Sichuan University, Chengdu, China
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19
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Gibson J, Fieldhouse R, Chan MM, Sadeghi-Alavijeh O, Burnett L, Izzi V, Persikov AV, Gale DP, Storey H, Savige J. Prevalence Estimates of Predicted Pathogenic COL4A3-COL4A5 Variants in a Population Sequencing Database and Their Implications for Alport Syndrome. J Am Soc Nephrol 2021; 32:2273-2290. [PMID: 34400539 PMCID: PMC8729840 DOI: 10.1681/asn.2020071065] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 05/05/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The reported prevalence of Alport syndrome varies from one in 5000 to one in 53,000 individuals. This study estimated the frequencies of predicted pathogenic COL4A3-COL4A5 variants in sequencing databases of populations without known kidney disease. METHODS Predicted pathogenic variants were identified using filtering steps based on the ACMG/AMP criteria, which considered collagen IV α3-α5 position 1 Gly to be critical domains. The population frequencies of predicted pathogenic COL4A3-COL4A5 variants were then determined per mean number of sequenced alleles. Population frequencies for compound heterozygous and digenic combinations were calculated from the results for heterozygous variants. RESULTS COL4A3-COL4A5 variants resulting in position 1 Gly substitutions were confirmed to be associated with hematuria (for each, P<0.001). Predicted pathogenic COL4A5 variants were found in at least one in 2320 individuals. p.(Gly624Asp) represented nearly half (16 of 33, 48%) of the variants in Europeans. Most COL4A5 variants (54 of 59, 92%) had a biochemical feature that potentially mitigated the clinical effect. The predicted pathogenic heterozygous COL4A3 and COL4A4 variants affected one in 106 of the population, consistent with the finding of thin basement membrane nephropathy in normal donor kidney biopsy specimens. Predicted pathogenic compound heterozygous variants occurred in one in 88,866 individuals, and digenic variants in at least one in 44,793. CONCLUSIONS The population frequencies for Alport syndrome are suggested by the frequencies of predicted pathogenic COL4A3-COL4A5 variants, but must be adjusted for the disease penetrance of individual variants and for the likelihood of already diagnosed disease and non-Gly substitutions. Disease penetrance may depend on other genetic and environmental factors.
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Affiliation(s)
- Joel Gibson
- The University of Melbourne Department of Medicine, Melbourne Health and Northern Health, Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Rachel Fieldhouse
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Melanie M.Y. Chan
- Department of Renal Medicine, University College London, London, United Kingdom,Genomics England, Queen Mary University of London, London, United Kingdom
| | - Omid Sadeghi-Alavijeh
- Department of Renal Medicine, University College London, London, United Kingdom,Genomics England, Queen Mary University of London, London, United Kingdom
| | - Leslie Burnett
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Valerio Izzi
- Center for Cell-Matrix Research and Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Anton V. Persikov
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey
| | - Daniel P. Gale
- Department of Renal Medicine, University College London, London, United Kingdom,Genomics England, Queen Mary University of London, London, United Kingdom
| | - Helen Storey
- Molecular Genetics, Viapath Laboratories, Guy’s Hospital, London, United Kingdom
| | - Judy Savige
- The University of Melbourne Department of Medicine, Melbourne Health and Northern Health, Royal Melbourne Hospital, Parkville, Victoria, Australia
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20
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Tang S, Yonezawa T, Maeda Y, Ono M, Maeba T, Miyoshi T, Momota R, Tomono Y, Oohashi T. Lack of collagen α6(IV) chain in mice does not cause severe-to-profound hearing loss or cochlear malformation, a distinct phenotype from nonsyndromic hearing loss with COL4A6 missense mutation. PLoS One 2021; 16:e0249909. [PMID: 33848312 PMCID: PMC8043391 DOI: 10.1371/journal.pone.0249909] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 03/26/2021] [Indexed: 11/18/2022] Open
Abstract
Congenital hearing loss affects 1 in every 1000 births, with genetic mutations contributing to more than 50% of all cases. X-linked nonsyndromic hereditary hearing loss is associated with six loci (DFNX1-6) and five genes. Recently, the missense mutation (c.1771G>A, p.Gly591Ser) in COL4A6, encoding the basement membrane (BM) collagen α6(IV) chain, was shown to be associated with X-linked congenital nonsyndromic hearing loss with cochlear malformation. However, the mechanism by which the COL4A6 mutation impacts hereditary hearing loss has not yet been elucidated. Herein, we investigated Col4a6 knockout (KO) effects on hearing function and cochlear formation in mice. Immunohistochemistry showed that the collagen α6(IV) chain was distributed throughout the mouse cochlea within subepithelial BMs underlying the interdental cells, inner sulcus cells, basilar membrane, outer sulcus cells, root cells, Reissner's membrane, and perivascular BMs in the spiral limbus, spiral ligament, and stria vascularis. However, the click-evoked auditory brainstem response analysis did not show significant changes in the hearing threshold of Col4a6 KO mice compared with wild-type (WT) mice with the same genetic background. In addition, the cochlear structures of Col4a6 KO mice did not exhibit morphological alterations, according to the results of high-resolution micro-computed tomography and histology. Hence, loss of Col4a6 gene expression in mice showed normal click ABR thresholds and normal cochlear formation, which differs from humans with the COL4A6 missense mutation c.1771G>A, p.Gly591Ser. Therefore, the deleterious effects in the auditory system caused by the missense mutation in COL4A6 are likely due to the dominant-negative effects of the α6(IV) chain and/or α5α6α5(IV) heterotrimer with an aberrant structure that would not occur in cases with loss of gene expression.
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Affiliation(s)
- Shaoying Tang
- Department of Molecular Biology and Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Tomoko Yonezawa
- Department of Molecular Biology and Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
- * E-mail:
| | - Yukihide Maeda
- Department of Otolaryngology-Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Mitsuaki Ono
- Department of Molecular Biology and Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Takahiro Maeba
- Department of Molecular Biology and Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Toru Miyoshi
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Ryusuke Momota
- Department of Human Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Yasuko Tomono
- Division of Molecular and Cell Biology, Shigei Medical Research Institute, Okayama, Japan
| | - Toshitaka Oohashi
- Department of Molecular Biology and Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
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21
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Utility of glomerular Gd-IgA1 staining for indistinguishable cases of IgA nephropathy or Alport syndrome. Clin Exp Nephrol 2021; 25:779-787. [PMID: 33743099 DOI: 10.1007/s10157-021-02054-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/11/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND Pathological findings in Alport syndrome frequently show mesangial proliferation and sometimes incidental IgA deposition, in addition to unique glomerular basement membrane (GBM) changes including thin basement membrane and/or lamellation. However, similar GBM abnormalities are also often observed in IgA nephropathy. Both diseases are also known to show hematuria, proteinuria, and sometimes macrohematuria when associated with viral infection. Therefore, it can be difficult to make a differential diagnosis, even based on clinical and pathological findings. Some recent articles demonstrated that galactose-deficient IgA1 (Gd-IgA1)-specific monoclonal antibody (KM55) could potentially enable incidental IgA deposition to be distinguished from IgA nephropathy. METHODS We performed comprehensive gene screening and glomerular Gd-IgA1 and type IV collagen α5 chain immunostaining for five cases with both IgA deposition and GBM changes to confirm that Gd-IgA1 can help to distinguish these two diseases. RESULTS Four of the cases were genetically diagnosed with Alport syndrome (Cases 1-4) and one was IgA nephropathy with massive GBM changes, which had a negative gene test result (Case 5). In Cases 1-4, glomerular Gd-IgA1 deposition was not detected, although there was positivity for IgA in the mesangial area. In Case 5, glomerular Gd-IgA1 deposition was observed. CONCLUSION Gd-IgA1 expression analysis could clearly differentiate these two disorders. This approach can be applied to identify these two diseases showing identical clinical and pathological findings.
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22
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Nozu K, Takaoka Y, Kai H, Takasato M, Yabuuchi K, Yamamura T, Horinouchi T, Sakakibara N, Ninchoji T, Nagano C, Iijima K. Genetic background, recent advances in molecular biology, and development of novel therapy in Alport syndrome. Kidney Res Clin Pract 2020; 39:402-413. [PMID: 33214343 PMCID: PMC7771000 DOI: 10.23876/j.krcp.20.111] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/06/2020] [Accepted: 08/08/2020] [Indexed: 12/18/2022] Open
Abstract
Alport syndrome (AS) is a progressive inherited kidney disease characterized by hearing loss and ocular abnormalities. There are three forms of AS depending on inheritance mode: X-linked Alport syndrome (XLAS), autosomal recessive AS (ARAS), and autosomal dominant AS (ADAS). XLAS is caused by pathogenic variants in COL4A5, which encodes type IV collagen α5 chain, while ADAS and ARAS are caused by variants in COL4A3 or COL4A4, which encode type IV collagen α3 or α4 chain, respectively. In male XLAS or ARAS cases, end-stage kidney disease (ESKD) develops around a median age of 20 to 30 years old, while female XLAS or ADAS cases develop ESKD around a median age of 60 to 70 years old. The diagnosis of AS is dependent on either genetic or pathological findings. However, determining the pathogenicity of the variants detected by gene tests can be difficult. Recently, we applied the following molecular investigation tools to determine pathogenicity: 1) in silico and in vitro trimer formation assay of α345 chains to assess triple helix formation ability, 2) kidney organoids constructed from patients’ induced pluripotent stem cells to identify α5 chain expression on the glomerular basement membrane, and 3) in vitro splicing assay to detect aberrant splicing to determine the pathogenicity of variants. In this review article, we discuss the genetic background and novel assays for determining the pathogenicity of variants. We also discuss the current treatment approaches and introduce exon skipping therapy as one potential treatment option.
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Affiliation(s)
- Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yutaka Takaoka
- Division of Medical Informatics and Bioinformatics, Kobe University Hospital, Kobe, Japan
| | - Hirofumi Kai
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Minoru Takasato
- Laboratory for Human Organogenesis, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan.,Laboratory of Molecular Cell Biology and Development, Department of Animal Development and Physiology, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Kensuke Yabuuchi
- Laboratory for Human Organogenesis, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takeshi Ninchoji
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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23
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Xu Z, Chen J, Yu W, Li X, Lin B, Lai D, Xu A, Tang Y. New COL4A5 mutation in IgA nephropathy. Postgrad Med J 2020; 98:13-17. [PMID: 33087535 DOI: 10.1136/postgradmedj-2020-138625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/09/2020] [Accepted: 10/03/2020] [Indexed: 01/24/2023]
Abstract
PURPOSE IgA nephropathy (IgAN) is the most common type of primary glomerulonephritis and a leading cause of chronic kidney disease (CKD) and end-stage kidney disease (ESKD). Recently, some case reports have shown that COL4A5 mutation is associated with IgAN. Here, we identified a new COL4A5 gene mutation in IgAN in a Chinese family. MATERIALS AND METHODS In the present study, the proband and his 23-year-old younger brother were both diagnosed with IgAN, manifested as haematuria, proteinuria and chronic kidney injury without hearing loss or ocular symptoms. Additionally, the proband's 30-year-old younger brother, also diagnosed with ESKD, had been undergoing dialysis for 2 years with normal hearing and eyesight. To exclude genetic disease, we conducted whole-exome sequencing and Sanger sequencing assays. RESULTS We found a new mutation in the COL4A5 gene (chrX:107 814 698, c.438+2->AAACCAATTATA-), a novel insertion mutation. Using vector transcription and Minigene transcriptional analyses, we verified, for the first time, the novel mutation pathogenicity of the COL4A5 gene. CONCLUSION Together with other published data, we suggest that genetic screening should be performed in IgAN, particularly for patients with a familial history. The effects of different mutated splice sites of the COL4A5 gene, as well as the tissue specificity of the splicing machinery contributing to the pathogenesis and prognosis of IgAN, remains unclear and warrants further exploration in the future.
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Affiliation(s)
- Zhenjian Xu
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Junzhe Chen
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Department of Nephrology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Wenjuan Yu
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Department of Nephrology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Xiaomei Li
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Department of Nephrology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Baojuan Lin
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Department of Nephrology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Deyuan Lai
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Department of Nephrology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Anping Xu
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Department of Nephrology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Ying Tang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China .,Department of Nephrology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
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24
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Horinouchi T, Yamamura T, Nagano C, Sakakibara N, Ishiko S, Aoto Y, Rossanti R, Nakanishi K, Shima Y, Morisada N, Iijima K, Nozu K. Heterozygous Urinary Abnormality-Causing Variants of COL4A3 and COL4A4 Affect Severity of Autosomal Recessive Alport Syndrome. KIDNEY360 2020; 1:936-942. [PMID: 35369551 DOI: 10.34067/kid.0000372019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 07/15/2020] [Indexed: 11/27/2022]
Abstract
Background Autosomal recessive Alport syndrome (ARAS) is an inherited renal disorder caused by homozygous and compound heterozygous mutations in COL4A3 or COL4A4, but the prognostic predictors for this disorder are not yet fully understood. Recently, the magnitude of the clinical spectrum of the COL4A3 and COL4A4 heterozygous state has attracted attention. This spectrum includes asymptomatic carriers of ARAS, benign familial hematuria, thin basement membrane disease, and autosomal dominant Alport syndrome. Methods We retrospectively analyzed 49 patients with ARAS from 41 families with a median age of 19 years to examine the clinical features and prognostic factors of ARAS, including the associated genotypes. Results The median age of patients with ARAS at ESKD onset was 27 years. There was no significant association between the presence or absence of hearing loss or truncating mutations and renal prognosis. However, there was a statistically significant correlation between renal prognosis and heterozygous variants that cause urinary abnormalities. Where the urinary abnormality-causing variant was absent or present in only one allele, the median age of ESKD onset was 45 years, whereas the same variant present on both alleles was associated with an age of onset of 15 years (P<0.001). Conclusions This study was the first to demonstrate the clinical importance in ARAS of focusing on variants in COL4A3 or COL4A4 that cause urinary abnormalities in both the homozygous or heterozygous state. Although heterozygous mutation carriers of COL4A3 and COL4A4 comprise a broad clinical spectrum, clinical information regarding each variant is important for predicting ARAS prognosis.
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Affiliation(s)
- Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kusunoki-cho, Chuo, Kobe, Hyogo, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kusunoki-cho, Chuo, Kobe, Hyogo, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kusunoki-cho, Chuo, Kobe, Hyogo, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kusunoki-cho, Chuo, Kobe, Hyogo, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kusunoki-cho, Chuo, Kobe, Hyogo, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kusunoki-cho, Chuo, Kobe, Hyogo, Japan
| | - Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kusunoki-cho, Chuo, Kobe, Hyogo, Japan
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of the Ryukyus, Uehara, Nishihara-cho, Tyutou, Okinawa, Japan
| | - Yuko Shima
- Department of Pediatrics, Wakayama Medical University, Kimiidera, Wakayama, Wakayama Prefecture, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kusunoki-cho, Chuo, Kobe, Hyogo, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kusunoki-cho, Chuo, Kobe, Hyogo, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kusunoki-cho, Chuo, Kobe, Hyogo, Japan
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25
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Kashtan CE. An update on current and potential genetic insights and diagnosis of Alport syndrome. Expert Opin Orphan Drugs 2020. [DOI: 10.1080/21678707.2020.1784722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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26
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Yamamura T, Horinouchi T, Nagano C, Omori T, Sakakibara N, Aoto Y, Ishiko S, Nakanishi K, Shima Y, Nagase H, Takeda H, Rossanti R, Ye MJ, Nozu Y, Ishimori S, Ninchoji T, Kaito H, Morisada N, Iijima K, Nozu K. Genotype-phenotype correlations influence the response to angiotensin-targeting drugs in Japanese patients with male X-linked Alport syndrome. Kidney Int 2020; 98:1605-1614. [PMID: 32712167 DOI: 10.1016/j.kint.2020.06.038] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 06/03/2020] [Accepted: 06/26/2020] [Indexed: 12/12/2022]
Abstract
Early kidney failure in the hereditary type IV collagen disease, Alport syndrome, can be delayed by renin-angiotensin inhibitors. However, whether all patients and all different genotypes respond equally well to this kidney-protective therapy remains unclear. Here, we performed a retrospective study on 430 patients with male X-linked Alport syndrome to examine the relationships among kidney prognosis, genotype, and treatment effect in a large cohort of Japanese patients. We analyzed the clinical features, genotype-phenotype correlation, and kidney survival period for patients treated with or without renin-angiotensin inhibitors. As a result, the median kidney survival period of patients in this cohort was found to be at 35 years with a strong genotype-phenotype correlation. The median age at the onset of end stage kidney disease (ESKD) significantly differed between patients treated with and without renin-angiotensin inhibitors (over 50 years versus 28 years, respectively). Moreover, these drugs delayed the onset of ESKD in patients with truncating variants for 12 years, extending the median age from 16 years to 28 years. Thus, our results confirmed a strong genotype-phenotype correlation in patients with male X-linked Alport syndrome. Additionally, it was suggested that renin-angiotensin inhibitors could significantly delay ESKD progression. Despite these therapies, patients with truncating variants developed ESKD at the median age of 28 years.
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Affiliation(s)
- Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Takashi Omori
- Clinical and Translational Research Center, Kobe University Hospital, Kobe, Hyogo, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of the Ryukyus, Nishihara, Okinawa, Japan
| | - Yuko Shima
- Department of Pediatrics, Wakayama Medical University, Wakayama, Japan
| | - Hiroaki Nagase
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Hiroki Takeda
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Ming Juan Ye
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Yoshimi Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Shingo Ishimori
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Takeshi Ninchoji
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Hiroshi Kaito
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
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Zhang L, Sun BC, Zhao BG, Ma QS. An overview of the multi-pronged approach in the diagnosis of Alport syndrome for 22 children in Northeast China. BMC Nephrol 2020; 21:294. [PMID: 32703181 PMCID: PMC7379802 DOI: 10.1186/s12882-020-01962-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 07/17/2020] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Alport syndrome (AS) is a kind of progressive hereditary nephritis induced by mutations of different genes that encode collagen IV. The affected individuals usually develop hematuria during childhood, accompanying with gradual deterioration of renal functions. In this study, the multi-pronged approach was employed to improve the diagnosis of AS. METHODS Twenty-two children were diagnosed and treated at the Department of Pediatric Nephrology of Jilin University First Hospital between January 2017 and January 2020 using the multi-pronged approach. The following information was collected from patients, including age of onset, age at diagnosis, clinical manifestations, family history, renal pathology and genotype. RESULTS All these 22 children were diagnosed with Alport syndrome according to the diagnostic criteria formulated by the Japanese Society of Nephrology (2015), among them, only 13 children met the diagnostic criteria released in 1988. All the 22 patients presented with hematuria, and proteinuria to varying degrees was observed in some patients. Three children suffered from hearing loss, but no child in the cohort had any visual problem or renal failure. Meanwhile, five patients were estimated to be at Stage 2, whereas the remaining 17 cases were at Stage 0. Renal biopsies were performed in 18 patients, including 14 showing glomerular basement membranes (GBM)-specific abnormalities. Moreover, 13 children were detected with mutations of genes encoding collagen IV. CONCLUSIONS The multi-pronged approach helps to improve the diagnosis of AS. Most patients do not have renal failure during childhood, but close assessment and monitoring are necessary. Also, the advancements in treatment are reviewed.
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Affiliation(s)
- Li Zhang
- Department of Pediatric Nephrology, First Hospital, Jilin University, Changchun, 130021 Jilin China
| | - Bai-chao Sun
- Department of Pediatric Nephrology, First Hospital, Jilin University, Changchun, 130021 Jilin China
| | - Bing-gang Zhao
- Department of Pediatric Nephrology, First Hospital, Jilin University, Changchun, 130021 Jilin China
| | - Qing-shan Ma
- Department of Pediatric Nephrology, First Hospital, Jilin University, Changchun, 130021 Jilin China
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28
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Kashtan CE. Alport Syndrome: Achieving Early Diagnosis and Treatment. Am J Kidney Dis 2020; 77:272-279. [PMID: 32712016 DOI: 10.1053/j.ajkd.2020.03.026] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 03/24/2020] [Indexed: 12/11/2022]
Abstract
Alport syndrome is a genetically and phenotypically heterogeneous disorder of glomerular, cochlear, and ocular basement membranes resulting from mutations in the collagen IV genes COL4A3, COL4A4, and COL4A5. Alport syndrome can be transmitted as an X-linked, autosomal recessive, or autosomal dominant disorder. Individuals with Alport syndrome have a significant lifetime risk for kidney failure, as well as sensorineural deafness and ocular abnormalities. The availability of effective intervention for Alport syndrome-related kidney disease makes early diagnosis crucial, but this can be impeded by the genotypic and phenotypic complexity of the disorder. This review presents an approach to enhancing early diagnosis and achieving optimal outcomes.
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Affiliation(s)
- Clifford E Kashtan
- Pediatric Nephrology, University of Minnesota Medical School, Minneapolis, MN.
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Araki Y, Kawaguchi A, Sakakibara N, Nagaoka Y, Yamamura T, Horinouchi T, Nagano C, Morisada N, Iijima K, Nozu K. Poststreptococcal acute glomerulonephritis can be a risk factor for accelerating kidney dysfunction in Alport syndrome: a case experience. CEN Case Rep 2020; 9:418-422. [PMID: 32592137 DOI: 10.1007/s13730-020-00498-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 06/17/2020] [Indexed: 11/30/2022] Open
Abstract
Alport syndrome (AS) is a progressive kidney disease. Male cases with X-linked AS (XLAS) are reported to develop end-stage kidney disease (ESKD) at the age of around 20-30 years. One risk factor for developing ESKD at a young age is a genotype of having truncating variants in the COL4A5 gene. However, to date, other such factors have remained unclear. Here, we describe a 15-year-old Japanese boy with XLAS who had a missense variant in the COL4A5 gene. He presented with gross hematuria, severe proteinuria, oliguria, systemic edema, body weight gain, and hypertension after pharyngitis. Blood examination showed kidney dysfunction, hypocomplementemia, and elevated antistreptolysin-O level. We diagnosed him with poststreptococcal acute glomerulonephritis (PSAGN) and he was stopped treatment by lisinopril, and received supportive treatment. However, he showed an unusual clinical course for PSAGN and, consequently, developed ESKD 15 months after the onset of PSAGN without recovery from the kidney dysfunction. This case showed that the onset of PSAGN can be a risk factor for AS patients to develop ESKD at a young age.
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Affiliation(s)
- Yoshinori Araki
- Department of Pediatric Nephrology, National Hospital Organization Hokkaido Medical Center, Sapporo, Japan
| | - Azusa Kawaguchi
- Department of Pediatric Nephrology, National Hospital Organization Hokkaido Medical Center, Sapporo, Japan
| | - Nana Sakakibara
- Department of Pediatric Nephrology, National Hospital Organization Hokkaido Medical Center, Sapporo, Japan.,Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Yoshinobu Nagaoka
- Department of Pediatric Nephrology, National Hospital Organization Hokkaido Medical Center, Sapporo, Japan.,Department of Pediatrics, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan.
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30
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Horinouchi T, Yamamura T, Minamikawa S, Nagano C, Sakakibara N, Nakanishi K, Shima Y, Morisada N, Ishiko S, Aoto Y, Nagase H, Takeda H, Rossanti R, Ishimori S, Kaito H, Matsuo M, Iijima K, Nozu K. Pathogenic evaluation of synonymous COL4A5 variants in X-linked Alport syndrome using a minigene assay. Mol Genet Genomic Med 2020; 8:e1342. [PMID: 32543079 PMCID: PMC7434753 DOI: 10.1002/mgg3.1342] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/13/2020] [Accepted: 05/19/2020] [Indexed: 12/20/2022] Open
Abstract
Background X‐linked Alport syndrome (XLAS) is a progressive, hereditary glomerular nephritis of variable severity caused by pathogenic COL4A5 variants. Currently, genetic testing is widely used for diagnosing XLAS; however, determining the pathogenicity of variants detected by such analyses can be difficult. Intronic variants or synonymous variants may cause inherited diseases by inducing aberrant splicing. Transcript analysis is necessary to confirm the pathogenicity of such variants, but it is sometimes difficult to extract mRNA directly from patient specimens. Methods In this study, we conducted in vitro splicing analysis using a hybrid minigene assay and specimens from three XLAS patients with synonymous variants causing aberrant splicing, including previously reported pathogenic mutations in the same codon. The variants were c.876 A>T (p.Gly292=), c.2358 A>G (p.Pro786=), and c.3906 A>G (p.Gln1302=). Results The results from our hybrid minigene assay were sufficient to predict splicing abnormalities; c.876 A>T cause 17‐bp del and 35‐bp del, c.2358 A>G cause exon 29 skipping, c.3906 A>G cause exon 42 skipping, which are very likely to cause pathogenicity. Further, patients carrying c.2358 A>G exhibited a mild phenotype that may have been associated with the presence of both normal and abnormally spliced transcripts. Conclusion The minigene system was shown to be a sensitive assay and a useful tool for investigating the pathogenicity of synonymous variants.
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Affiliation(s)
- Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shogo Minamikawa
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan
| | - Yuko Shima
- Department of Pediatrics, Wakayama Medical University, Wakayama, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroaki Nagase
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroki Takeda
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shingo Ishimori
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroshi Kaito
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masafumi Matsuo
- Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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31
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Yamamura T, Horinouchi T, Adachi T, Terakawa M, Takaoka Y, Omachi K, Takasato M, Takaishi K, Shoji T, Onishi Y, Kanazawa Y, Koizumi M, Tomono Y, Sugano A, Shono A, Minamikawa S, Nagano C, Sakakibara N, Ishiko S, Aoto Y, Kamura M, Harita Y, Miura K, Kanda S, Morisada N, Rossanti R, Ye MJ, Nozu Y, Matsuo M, Kai H, Iijima K, Nozu K. Development of an exon skipping therapy for X-linked Alport syndrome with truncating variants in COL4A5. Nat Commun 2020; 11:2777. [PMID: 32488001 PMCID: PMC7265383 DOI: 10.1038/s41467-020-16605-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 05/12/2020] [Indexed: 11/10/2022] Open
Abstract
Currently, there are no treatments for Alport syndrome, which is the second most commonly inherited kidney disease. Here we report the development of an exon-skipping therapy using an antisense-oligonucleotide (ASO) for severe male X-linked Alport syndrome (XLAS). We targeted truncating variants in exon 21 of the COL4A5 gene and conducted a type IV collagen α3/α4/α5 chain triple helix formation assay, and in vitro and in vivo treatment efficacy evaluation. We show that exon skipping enabled trimer formation, leading to remarkable clinical and pathological improvements including expression of the α5 chain on glomerular and the tubular basement membrane. In addition, the survival period was clearly prolonged in the ASO treated mice group. This data suggests that exon skipping may represent a promising therapeutic approach for treating severe male XLAS cases. Alport syndrome is a progressive inherited nephritis accompanied by sensorineural loss of hearing and ocular abnormalities, for which there is currently no effective therapy. Here, the authors develop an exon-skipping therapy using an antisense-oligonucleotide and show it is effective in mouse models.
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Affiliation(s)
- Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomomi Adachi
- Rare Disease Laboratories, Daiichi Sankyo Co., Ltd., Shinagawa, Tokyo, Japan
| | - Maki Terakawa
- Rare Disease Laboratories, Daiichi Sankyo Co., Ltd., Shinagawa, Tokyo, Japan
| | - Yutaka Takaoka
- Division of Medical Informatics and Bioinformatics, Kobe University Hospital, Kobe, Japan
| | - Kohei Omachi
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | | | - Kiyosumi Takaishi
- Rare Disease Laboratories, Daiichi Sankyo Co., Ltd., Shinagawa, Tokyo, Japan
| | - Takao Shoji
- Modality Research Laboratories, Daiichi Sankyo Co., Ltd., Shinagawa, Tokyo, Japan
| | - Yoshiyuki Onishi
- Modality Research Laboratories, Daiichi Sankyo Co., Ltd., Shinagawa, Tokyo, Japan
| | - Yoshito Kanazawa
- Modality Research Laboratories, Daiichi Sankyo Co., Ltd., Shinagawa, Tokyo, Japan
| | - Makoto Koizumi
- Modality Research Laboratories, Daiichi Sankyo Co., Ltd., Shinagawa, Tokyo, Japan
| | - Yasuko Tomono
- Division of Molecular Cell Biology, Shigei Medical Research Institute, Okayama, Japan
| | - Aki Sugano
- Division of Medical Informatics and Bioinformatics, Kobe University Hospital, Kobe, Japan
| | - Akemi Shono
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shogo Minamikawa
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Misato Kamura
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Yutaka Harita
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kenichiro Miura
- Department of Pediatric Nephrology, Tokyo Women's Medical University, Tokyo, Japan
| | - Shoichiro Kanda
- Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Ming Juan Ye
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yoshimi Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masafumi Matsuo
- Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan
| | - Hirofumi Kai
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.
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Trimerization and Genotype-Phenotype Correlation of COL4A5 Mutants in Alport Syndrome. Kidney Int Rep 2020; 5:718-726. [PMID: 32405592 PMCID: PMC7210609 DOI: 10.1016/j.ekir.2020.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/13/2020] [Accepted: 01/20/2020] [Indexed: 01/08/2023] Open
Abstract
Introduction Alport syndrome is a hereditary glomerulonephritis that results from the disruption of collagen α345(IV) heterotrimerization caused by mutation in COL4A3, COL4A4 or COL4A5 genes. Many clinical studies have elucidated the correlation between genotype and phenotype, but there is still much ambiguity and insufficiency. Here, we focused on the α345(IV) heterotrimerization of α5(IV) missense mutant as a novel factor to further understand the pathophysiology of Alport syndrome. Methods We selected 9 α5(IV) missense mutants with typical glycine substitutions that clinically differed in disease progression. To quantify the trimerization of each mutant, split nanoluciferase-fused α3/α5 mutants and α4 were transfected into the cells, and intracellular and secreted heterotrimer were detected by luminescence using an assay that we developed previously. Results Trimer formation and secretion patterns tended to be similar to the wild type in most of the mutations that did not show proteinuria at a young age. On the other hand, trimer secretion was significantly reduced in all the mutations that showed proteinuria and early onset of renal failure. One of these mutants has low ability of intracellular trimer formation, and the others had the defect of low-level secretion. In addition, the mutant that is assumed to be nonpathogenic has similar trimer formation and secretion pattern as wild-type α5(IV). Conclusion The result of cell-based α345(IV) heterotrimer formation assay was largely correlated with clinical genotype–phenotype. These trimerization assessments provide additional phenotypic considerations and may help to distinguish between pathogenic and nonpathogenic mutations.
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Minamikawa S, Miwa S, Inagaki T, Nishiyama K, Kaito H, Ninchoji T, Yamamura T, Nagano C, Sakakibara N, Ishimori S, Hara S, Yoshikawa N, Hirano D, Harada R, Hamada R, Matsunoshita N, Nagata M, Shima Y, Nakanishi K, Nagase H, Takeda H, Morisada N, Iijima K, Nozu K. Molecular mechanisms determining severity in patients with Pierson syndrome. J Hum Genet 2020; 65:355-362. [PMID: 31959872 DOI: 10.1038/s10038-019-0715-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 12/10/2019] [Accepted: 12/11/2019] [Indexed: 01/15/2023]
Abstract
Null variants in LAMB2 cause Pierson syndrome (PS), a severe congenital nephrotic syndrome with ocular and neurological defects. Patients' kidney specimens show complete negativity for laminin β2 expression on glomerular basement membrane (GBM). In contrast, missense variants outside the laminin N-terminal (LN) domain in LAMB2 lead to milder phenotypes. However, we experienced cases not showing these typical genotype-phenotype correlations. In this paper, we report six PS patients: four with mild phenotypes and two with severe phenotypes. We conducted molecular studies including protein expression and transcript analyses. The results revealed that three of the four cases with milder phenotypes had missense variants located outside the LN domain and one of the two severe PS cases had a homozygous missense variant located in the LN domain; these variant positions could explain their phenotypes. However, one mild case possessed a splicing site variant (c.3797 + 5G>A) that should be associated with a severe phenotype. Upon transcript analysis, this variant generated some differently sized transcripts, including completely normal transcript, which could have conferred the milder phenotype. In one severe case, we detected the single-nucleotide substitution of c.4616G>A located outside the LN domain, which should be associated with a milder phenotype. However, we detected aberrant splicing caused by the creation of a novel splice site by this single-base substitution. These are novel mechanisms leading to an atypical genotype-phenotype correlation. In addition, all four cases with milder phenotypes showed laminin β2 expression on GBM. We identified novel mechanisms leading to atypical genotype-phenotype correlation in PS.
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Affiliation(s)
- Shogo Minamikawa
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Saori Miwa
- Department of Pediatrics, Jikei University School of Medicine, Tokyo, Japan
| | - Tetsuji Inagaki
- Department of Pediatric Nephrology, Miyagi Children's Hospital, Sendai, Japan
| | - Kei Nishiyama
- Department of Pediatrics, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan
| | - Hiroshi Kaito
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takeshi Ninchoji
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shingo Ishimori
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shigeo Hara
- Department of Diagnostic Pathology, Kobe City Medical Center General Hospital, Kobe, Japan
| | | | - Daishi Hirano
- Department of Pediatrics, Jikei University School of Medicine, Tokyo, Japan
| | - Ryoko Harada
- Department of Nephrology, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | - Riku Hamada
- Department of Nephrology, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | | | - Michio Nagata
- Department of Kidney and Vascular Pathology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Yuko Shima
- Department of Pediatrics, Wakayama Medical University, Wakayama, Japan
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan
| | - Hiroaki Nagase
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroki Takeda
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.
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34
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Savige J. Alport syndrome: deducing the mode of inheritance from the presence of haematuria in family members. Pediatr Nephrol 2020; 35:59-66. [PMID: 30506145 DOI: 10.1007/s00467-018-4121-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 10/15/2018] [Accepted: 10/17/2018] [Indexed: 11/24/2022]
Abstract
The diagnosis of Alport syndrome is suspected when an individual has haematuria or renal failure, together with a hearing loss; haematuria or renal failure, and a family history of Alport syndrome; or a pathognomonic Alport feature, such as lenticonus, fleck retinopathy, a lamellated glomerular basement membrane (GBM), or a GBM that lacks the collagen IV α3α4α5 network. The diagnosis of Alport syndrome is optimally confirmed by the demonstration of a mutation in the COL4A5 gene or two mutations in trans in the COL4A3 or COL4A4 genes. In practice, genetic testing for Alport syndrome is not widely available, and even with testing, causative mutations are not demonstrated in 5% of cases. Often, haematuria is only known in some family members, and the other characteristic features are not present or have not been sought. Where Alport syndrome remains likely, it is important to distinguish between X-linked inheritance, which occurs in 85% of families, and autosomal recessive inheritance, in the remaining 15%. This distinction is important because different modes of inheritance mean that different family members are at risk of being affected. Clinicians generally rely on the presence of haematuria to identify affected individuals in families with suspected Alport syndrome and on the information from three-generational family trees to assess the likely mode of inheritance. While often helpful, this strategy can also be misleading. The major sources of error are families with few members or where few members are tested; families comprising mainly women, where the typical Alport features are absent; families where the father is not available for testing for haematuria; and families with a coincidental renal disease. These difficulties emphasise the helpfulness of genetic testing in distinguishing between X-linked and autosomal recessively inherited forms of Alport syndrome.
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Affiliation(s)
- Judy Savige
- Department of Medicine, Melbourne Health and Northern Health, The University of Melbourne, Parkville, 3050, Australia.
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Schapiro D, Daga A, Lawson JA, Majmundar AJ, Lovric S, Tan W, Warejko JK, Fessi I, Rao J, Airik M, Gee HY, Schneider R, Widmeier E, Hermle T, Ashraf S, Jobst-Schwan T, van der Ven AT, Nakayama M, Shril S, Braun DA, Hildebrandt F. Panel sequencing distinguishes monogenic forms of nephritis from nephrosis in children. Nephrol Dial Transplant 2019; 34:474-485. [PMID: 30295827 DOI: 10.1093/ndt/gfy050] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 01/21/2018] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Alport syndrome (AS) and atypical hemolytic-uremic syndrome (aHUS) are rare forms of chronic kidney disease (CKD) that can lead to a severe decline of renal function. Steroid-resistant nephrotic syndrome (SRNS) is more common than AS and aHUS and causes 10% of childhood-onset CKD. In recent years, multiple monogenic causes of AS, aHUS and SRNS have been identified, but their relative prevalence has yet to be studied together in a typical pediatric cohort of children with proteinuria and hematuria. We hypothesized that identification of causative mutations by whole exome sequencing (WES) in known monogenic nephritis and nephrosis genes would allow distinguishing nephritis from nephrosis in a typical pediatric group of patients with both proteinuria and hematuria at any level. METHODS We therefore conducted an exon sequencing (WES) analysis for 11 AS, aHUS and thrombotic thrombocytopenic purpura-causing genes in an international cohort of 371 patients from 362 families presenting with both proteinuria and hematuria before age 25 years. In parallel, we conducted either WES or high-throughput exon sequencing for 23 SRNS-causing genes in all patients. RESULTS We detected pathogenic mutations in 18 of the 34 genes analyzed, leading to a molecular diagnosis in 14.1% of families (51 of 362). Disease-causing mutations were detected in 3 AS-causing genes (4.7%), 3 aHUS-causing genes (1.4%) and 12 NS-causing genes (8.0%). We observed a much higher mutation detection rate for monogenic forms of CKD in consanguineous families (35.7% versus 10.1%). CONCLUSIONS We present the first estimate of relative frequency of inherited AS, aHUS and NS in a typical pediatric cohort with proteinuria and hematuria. Important therapeutic and preventative measures may result from mutational analysis in individuals with proteinuria and hematuria.
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Affiliation(s)
- David Schapiro
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ankana Daga
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jennifer A Lawson
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Amar J Majmundar
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Svjetlana Lovric
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Weizhen Tan
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jillian K Warejko
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Inés Fessi
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jia Rao
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Merlin Airik
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Heon Yung Gee
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ronen Schneider
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Eugen Widmeier
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Tobias Hermle
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Shazia Ashraf
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Tilman Jobst-Schwan
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Amelie T van der Ven
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Makiko Nakayama
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Shirlee Shril
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Daniela A Braun
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Friedhelm Hildebrandt
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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Roy S, Nalwa A, Keith J, Weck K, Singh H, Nickeleit V. Pseudolinear C4d deposits in a hereditary glomerulopathy caused by a rare NC1 collagen-4-alpha-5 missense mutation: a "new disease entity"? Ultrastruct Pathol 2019; 43:209-215. [PMID: 31682783 DOI: 10.1080/01913123.2019.1683666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
C4d positive glomerulopathies with pseudolinear capillary wall deposits caused by basement membrane (GBM) remodeling have sporadically been reported in renal transplants. Here we describe the case of a hypertensive 60 year-old male with a 5 month history of nephrotic range proteinuria in the setting of normal serum creatinine, complement and ANA levels. Work-up showed MGUS (IgG/kappa restricted). A diagnostic renal biopsy to search for monoclonal gammopathy of renal significance demonstrated thickened glomerular capillary walls with strong pseudolinear complement factor C4d deposits by immunofluorescence microscopy (IF); all other IF studies including stains for Col4A3 were unrevealing with only minor abnormalities seen for Col4A5. The strong and unusual C4d staining of undetermined direct diagnostic significance triggered additional electron microscopic studies uncovering marked structural GBM changes suggestive of a hereditary nephropathy. Further genetic testing revealed a very rare X-linked single missense mutation in the NC1 domain of Col4A5 (exon 51) with a single amino acid substitution (COL4A5 p.A1581S) that has thus far not been reported in hereditary nephropathies. Our case provides further support for pseudolinear glomerular C4d deposits as general markers of GBM remodeling, in our case an unexpected hereditary nephropathy in an older male. Pseudolinear C4d: a general signpost for architectural GBM disturbance and a stimulus for in-depth studies including electron microscopy.
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Affiliation(s)
- Sanjeet Roy
- Department of Pathology, Division of Nephropathology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Aasma Nalwa
- Department of Pathology, Division of Nephropathology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Jared Keith
- Blue Ridge Nephrology and Hypertension Center, Boone, NC, USA
| | - Karen Weck
- Department of Pathology, Molecular Genetics Laboratory, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - Harsharan Singh
- Department of Pathology, Division of Nephropathology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Volker Nickeleit
- Department of Pathology, Division of Nephropathology, University of North Carolina at Chapel Hill, Chapel Hill, United States
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Horinouchi T, Nozu K, Yamamura T, Minamikawa S, Nagano C, Sakakibara N, Nakanishi K, Shima Y, Morisada N, Ishiko S, Aoto Y, Nagase H, Takeda H, Rossanti R, Kaito H, Matsuo M, Iijima K. Determination of the pathogenicity of known COL4A5 intronic variants by in vitro splicing assay. Sci Rep 2019; 9:12696. [PMID: 31481700 PMCID: PMC6722096 DOI: 10.1038/s41598-019-48990-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 08/15/2019] [Indexed: 02/07/2023] Open
Abstract
X-linked Alport syndrome (XLAS) is a congenital renal disease caused by mutations in COL4A5. In XLAS cases suspected of being caused by aberrant splicing, transcript analysis needs to be conducted to determine splicing patterns and assess the pathogenicity. However, such analysis is not always available. We conducted a functional splicing assay using a hybrid minigene for seven COL4A5 intronic mutations: one was identified by us and six were found in the Human Gene Mutation Database. The minigene assay revealed exon skipping in four variants, exon skipping and a 10-bp insertion in one variant, and no change in one variant, which appeared not to be pathogenic. For one variant, our assay did not work. The results of all three cases for which transcript data were available were consistent with our assay results. Our findings may help to increase the accuracy of genetic test results and clarify the mechanisms causing aberrant splicing.
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Affiliation(s)
- Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan.
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Shogo Minamikawa
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of the Ryukyus, 207, Uehara, Nishihara-cho, Tyutou, Okinawa, 903-0125, Japan
| | - Yuko Shima
- Department of Pediatrics, Wakayama Medical University, 811-1, Kimiidera, Wakayama, Wakayama Prefecture, 641-8510, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Hiroaki Nagase
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Hiroki Takeda
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Hiroshi Kaito
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Masafumi Matsuo
- Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, 518, Arise, Ikawadani-cho, Nishi, Kobe, Hyogo, 651-2180, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
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Akihisa T, Sato M, Wakayama Y, Taneda S, Horita S, Hirose O, Makabe S, Kataoka H, Mori T, Sohara E, Uchida S, Nitta K, Mochizuki T. Glomerular Basement Membrane Protein Expression and the Diagnosis and Prognosis of Autosomal Dominant Alport Syndrome. Kidney Med 2019; 1:391-396. [PMID: 32734219 PMCID: PMC7380416 DOI: 10.1016/j.xkme.2019.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Alport syndrome is a hereditary glomerular nephritis associated with hearing loss and eye abnormalities and is classified as X-linked Alport syndrome, autosomal recessive Alport syndrome, and autosomal dominant Alport syndrome. Autosomal dominant Alport syndrome is caused by a mutation in the gene encoding type IV collagen α3 (α3[IV]); (COL4A3), or α4 (α4[IV]); (COL4A4). Autosomal dominant Alport syndrome progresses more gradually than male X-linked Alport syndrome and autosomal recessive Alport syndrome. Differentiating autosomal dominant Alport syndrome from thin basement membrane nephropathy, which shows better kidney prognosis, remains challenging. Because autosomal dominant Alport syndrome is linked to a heterozygous mutation, type IV collagen is produced by the wild-type allele, and all α(IV) chains are supposed to be normally expressed. In this study, the pathologic findings of a patient with Alport syndrome with a novel COL4A4 heterozygous nonsense mutation were investigated. We observed weaker staining of α5(IV) in the glomerular basement membrane and enhanced expressions of α2(IV), laminin, and fibronectin, which were assumed to be caused by compensatory mechanisms for lack of enough α3α4α5(IV) expression in the glomerular basement membrane. These findings may be useful not only for differentially diagnosing autosomal dominant Alport syndrome from thin basement membrane nephropathy, but also for determining the extent of progression and predicting kidney prognosis.
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Affiliation(s)
- Taro Akihisa
- Department of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masayo Sato
- Department of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yoshie Wakayama
- Department of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Sekiko Taneda
- Division of Pathology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shigeru Horita
- Clinical Research Division for Polycystic Kidney Disease, Department of Medicine, Kidney Center, Tokyo Women's Medical University, Tokyo Medical and Dental University, Tokyo, Japan
| | - Orie Hirose
- Department of Pathology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shiho Makabe
- Department of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hiroshi Kataoka
- Department of Medicine, Tokyo Medical and Dental University, Tokyo, Japan.,Clinical Research Division for Polycystic Kidney Disease, Department of Medicine, Kidney Center, Tokyo Women's Medical University, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takayasu Mori
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kosaku Nitta
- Department of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Toshio Mochizuki
- Department of Medicine, Tokyo Medical and Dental University, Tokyo, Japan.,Clinical Research Division for Polycystic Kidney Disease, Department of Medicine, Kidney Center, Tokyo Women's Medical University, Tokyo Medical and Dental University, Tokyo, Japan
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Yamamura T, Nozu K, Minamikawa S, Horinouchi T, Sakakibara N, Nagano C, Aoto Y, Ishiko S, Nakanishi K, Shima Y, Nagase H, Rossanti R, Ye MJ, Nozu Y, Ishimori S, Morisada N, Kaito H, Iijima K. Comparison between conventional and comprehensive sequencing approaches for genetic diagnosis of Alport syndrome. Mol Genet Genomic Med 2019; 7:e883. [PMID: 31364286 PMCID: PMC6732293 DOI: 10.1002/mgg3.883] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 06/05/2019] [Accepted: 07/05/2019] [Indexed: 12/19/2022] Open
Abstract
Background Alport syndrome (AS) is a hereditary disease caused by mutations in COL4A3‐5 genes. Recently, comprehensive genetic analysis has become the first‐line diagnostic tool for AS. However, no reports comparing mutation identification rates between conventional sequencing and comprehensive screening have been published. Methods In this study, 441 patients clinically suspected of having AS were divided into two groups and compared. The initial mutational analysis method involved targeted exome sequencing using next‐generation sequencing (NGS) (n = 147, NGS group) or Sanger sequencing for COL4A3/COL4A4/COL4A5 (n = 294, Sanger group). Results In the NGS group, 126 patients (86%) were diagnosed with AS by NGS, while two had pathogenic mutations in other genes, NPHS1 and EYA1. Further, 239 patients (81%) were diagnosed with AS by initial analysis in the Sanger group. Thirteen patients who were negative for mutation detection in the Sanger group were analyzed by NGS; three were diagnosed with AS. Two had mutations in CLCN5 or LAMB2. The final variant detection rate was 90%. Discussion Our results reveal that Sanger sequencing and targeted exome sequencing have high diagnostic ability. NGS also has the advantage of detecting other inherited kidney diseases and pathogenic mutations missed by Sanger sequencing.
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Affiliation(s)
- Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Shogo Minamikawa
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of the Ryukyus, Nishihara, Okinawa, Japan
| | - Yuko Shima
- Department of Pediatrics, Wakayama Medical University, Wakayama, Japan
| | - Hiroaki Nagase
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Ming J Ye
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Yoshimi Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Shingo Ishimori
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Hiroshi Kaito
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
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Identification of a novel COL4A5 mutation in the proband initially diagnosed as IgAN from a Chinese family with X-linked Alport syndrome. SCIENCE CHINA-LIFE SCIENCES 2019; 62:1572-1579. [PMID: 31209800 DOI: 10.1007/s11427-018-9545-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 02/16/2019] [Indexed: 01/20/2023]
Abstract
Alport syndrome (AS) is a hereditary progressive nephropathy characterized by hematuria, ultrastructural lesions of the glomerular basement membrane, ocular lesions and sensorineural hearing loss. Germline mutations of COL4A5 are associated with X-linked AS with an extreme phenotypic heterogeneity. Here, we investigated a Chinese family with Alport syndrome. The proband was a 9-year-old boy with hematuria and proteinuria. Based on the test results of renal biopsy and immunofluorescence, the proband was initially diagnosed as IgA nephropathy and the treatment was recommended accordingly. Meanwhile, we found that the treatment outcome was poor. Therefore, for proper clinical diagnosis and appropriate treatment, targeted exome-based next-generation sequencing has been undertaken. We identified a novel hemizygous single nucleotide deletion c.1902delA in COL4A5 gene. Segregation analysis identified that this novel mutation is co-segregated among the affected family members but absent in unaffected family members. The clinical diagnosis of the proband was revised as AS accompanied by IgA nephropathy, which has been rarely reported. Our findings demonstrated the significance of the application of Genetic screening, expanded the mutation spectrum of COL4A5 associated AS patients with atypical renal phenotypes and provided a good lesson to be learned from our detour during the diagnosis.
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Zhang Y, Ding J, Zhang H, Yao Y, Xiao H, Wang S, Wang F. Effect of heterozygous pathogenic COL4A3 or COL4A4 variants on patients with X-linked Alport syndrome. Mol Genet Genomic Med 2019; 7:e647. [PMID: 30883042 PMCID: PMC6503168 DOI: 10.1002/mgg3.647] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/03/2019] [Accepted: 02/26/2019] [Indexed: 12/12/2022] Open
Abstract
Background Alport syndrome is an inherited renal disease caused by mutations in COL4A3, COL4A4, or COL4A5 genes. Coexisting mutations in either two of the three genes in Alport patients have been reported recently. However, the effect of heterozygous mutations in COL4A3 or COL4A4 genes in X‐linked Alport syndrome (XLAS) patients is unclear. Methods Using targeted next‐generation sequencing, six unrelated Chinese children were identified to have a combination of a pathogenic variant in COL4A5 and a heterozygous mutation in COL4A3 or COL4A4. They were three males and three females. Another three XLAS males each with only one pathogenic variant in COL4A5 were included. The clinical data were analyzed and compared between the males in two groups (group 1, males with a pathogenic variant in COL4A5 and a heterozygous pathogenic variant in COL4A3 or COL4A4; group 2, males with only one pathogenic variant in COL4A5). Results Patients with XLAS who also had heterozygous pathogenic COL4A3 or COL4A4 variants accounted for 1% of Alport syndrome. In this study, three children showed coexisting pathogenic variants in COL4A5 and COL4A3. Two children showed pathogenic variants in COL4A5 and COL4A4. One child had pathogenic variants in the three COL4A3‐5 genes, in which the pathogenic variant in COL4A5 was de novo and the pathogenic variants in COL4A4 and COL4A3 were inherited independently (in trans). The site and type of mutations in COL4A5 were similar between the two groups. It was revealed that males in group 1 presented more severe proteinuria than males in group 2 (p < 0.05). Conclusion The present study provides further evidence for complicated genotype in Alport syndrome. For the first time, we reported a case with three pathogenic variants in COL4A5, COL4A3, and COL4A4 genes. Moreover, we found that heterozygous pathogenic COL4A3 or COL4A4 variants are likely to make XLAS disease more serious.
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Affiliation(s)
- Yanqin Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jie Ding
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Hongwen Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yong Yao
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Huijie Xiao
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Suxia Wang
- Department of Electron Microscopy, Peking University First Hospital, Beijing, China
| | - Fang Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
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Imafuku A, Nozu K, Sawa N, Hasegawa E, Hiramatsu R, Kawada M, Hoshino J, Tanaka K, Ishii Y, Takaichi K, Fujii T, Ohashi K, Iijima K, Ubara Y. Autosomal dominant form of type IV collagen nephropathy exists among patients with hereditary nephritis difficult to diagnose clinicopathologically. Nephrology (Carlton) 2019; 23:940-947. [PMID: 28704582 PMCID: PMC6767408 DOI: 10.1111/nep.13115] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2017] [Indexed: 01/01/2023]
Abstract
The study revealed that 69% of families with hereditary nephritis that was difficult to diagnose clinicopathologically had heterozygous mutations of COL4A3/A4 (TBMN/ADAS). The finding suggests the importance of genetic testing in appropriate patients. Aim Type IV collagen nephropathies include Alport Syndrome and thin basement membrane nephropathy (TBMN), which are caused by mutations in COL4A3/A4/A5 genes. Recently, reports of patients with heterozygous mutations in COL4A3/A4 have been increasing. The clinical course of these patients has a wide variety, and they are diagnosed as TBMN, autosomal dominant Alport syndrome (ADAS), or familial focal segmental glomerular sclerosis. However, diagnosis, frequency and clinicopathological manifestation of them remains unclear. We tested COL4A3/A4/A5 genes in patients with hereditary nephritis that was difficult to diagnose clinicopathologically, and investigated who should undergo such testing. Methods We performed immunostaining for α5 chain of type IV collagen [α5 (IV)] in 27 patients from 21 families who fitted the following criteria: (i) haematuria and proteinuria (± renal dysfunction); (ii) family history of haematuria, proteinuria, and/or renal dysfunction (autosomal dominant inheritance); (iii) no specific glomerulonephritis; and (iv) thinning, splitting, or lamellation of the glomerular basement membrane (GBM) on electron microscopy. Then we performed genetic testing in 19 patients from 16 families who showed normal α5 (IV) patterns. We conducted a retrospective analysis of their clinicopathological findings. Results Among 16 families, 69% were detected heterozygous mutations in COL4A3/A4, suggesting the diagnosis of TBMN/ADAS. Twenty‐one percent of patients developed end stage renal disease. All patients showed thinning of GBM, which was accompanied by splitting or lamellation in seven patients. Conclusion A considerable fraction of patients with hereditary nephritis that is difficult to diagnose clinicopathologically have TBMN/ADAS. It is important to recognize TBMN/ADAS and perform genetic testing in appropriate patients.
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Affiliation(s)
- Aya Imafuku
- Nephrology Center, Toranomon Hospital, Minato-ku, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University, Kobe, Japan
| | - Naoki Sawa
- Nephrology Center, Toranomon Hospital, Minato-ku, Japan
| | - Eiko Hasegawa
- Nephrology Center, Toranomon Hospital, Minato-ku, Japan
| | | | | | | | - Kiho Tanaka
- Nephrology Center, Toranomon Hospital, Minato-ku, Japan
| | - Yasuo Ishii
- Nephrology Center, Toranomon Hospital, Minato-ku, Japan
| | - Kenmei Takaichi
- Nephrology Center, Toranomon Hospital, Minato-ku, Japan.,Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Minato-ku, Japan
| | - Takeshi Fujii
- Department of Pathology, Toranomon Hospital, Minato-ku, Japan
| | - Kenichi Ohashi
- Department of Pathology, Toranomon Hospital, Minato-ku, Japan.,Department of Pathology, Yokohama City University, Graduate School of Medicine, Yokohama-shi, Japan
| | | | - Yoshifumi Ubara
- Nephrology Center, Toranomon Hospital, Minato-ku, Japan.,Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Minato-ku, Japan
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Abstract
Alport syndrome (AS) is a progressive hereditary renal disease that is characterized by sensorineural hearing loss and ocular abnormalities. It is divided into three modes of inheritance, namely, X-linked Alport syndrome (XLAS), autosomal recessive AS (ARAS), and autosomal dominant AS (ADAS). XLAS is caused by pathogenic variants in COL4A5, while ADAS and ARAS are caused by those in COL4A3/COL4A4. Diagnosis is conventionally made pathologically, but recent advances in comprehensive genetic analysis have enabled genetic testing to be performed for the diagnosis of AS as first-line diagnosis. Because of these advances, substantial information about the genetics of AS has been obtained and the genetic background of this disease has been revealed, including genotype-phenotype correlations and mechanisms of onset in some male XLAS cases that lead to milder phenotypes of late-onset end-stage renal disease (ESRD). There is currently no radical therapy for AS and treatment is only performed to delay progression to ESRD using nephron-protective drugs. Angiotensin-converting enzyme inhibitors can remarkably delay the development of ESRD. Recently, some new drugs for this disease have entered clinical trials or been developed in laboratories. In this article, we review the diagnostic strategy, genotype-phenotype correlation, mechanisms of onset of milder phenotypes, and treatment of AS, among others.
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Nozu K, Nakanishi K, Abe Y, Udagawa T, Okada S, Okamoto T, Kaito H, Kanemoto K, Kobayashi A, Tanaka E, Tanaka K, Hama T, Fujimaru R, Miwa S, Yamamura T, Yamamura N, Horinouchi T, Minamikawa S, Nagata M, Iijima K. A review of clinical characteristics and genetic backgrounds in Alport syndrome. Clin Exp Nephrol 2018; 23:158-168. [PMID: 30128941 PMCID: PMC6510800 DOI: 10.1007/s10157-018-1629-4] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 08/06/2018] [Indexed: 01/15/2023]
Abstract
Alport syndrome (AS) is a progressive hereditary renal disease that is characterized by sensorineural hearing loss and ocular abnormalities. It is divided into three modes of inheritance, namely, X-linked Alport syndrome (XLAS), autosomal recessive AS (ARAS), and autosomal dominant AS (ADAS). XLAS is caused by pathogenic variants in COL4A5, while ADAS and ARAS are caused by those in COL4A3/COL4A4. Diagnosis is conventionally made pathologically, but recent advances in comprehensive genetic analysis have enabled genetic testing to be performed for the diagnosis of AS as first-line diagnosis. Because of these advances, substantial information about the genetics of AS has been obtained and the genetic background of this disease has been revealed, including genotype–phenotype correlations and mechanisms of onset in some male XLAS cases that lead to milder phenotypes of late-onset end-stage renal disease (ESRD). There is currently no radical therapy for AS and treatment is only performed to delay progression to ESRD using nephron-protective drugs. Angiotensin-converting enzyme inhibitors can remarkably delay the development of ESRD. Recently, some new drugs for this disease have entered clinical trials or been developed in laboratories. In this article, we review the diagnostic strategy, genotype–phenotype correlation, mechanisms of onset of milder phenotypes, and treatment of AS, among others.
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Affiliation(s)
- Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan
| | - Yoshifusa Abe
- Children Medical Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa, Japan
| | - Tomohiro Udagawa
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shinichi Okada
- Division of Pediatrics and Perinatology, Faculty of Medicine, Tottori University, Tottori, Japan
| | - Takayuki Okamoto
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Hiroshi Kaito
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Katsuyoshi Kanemoto
- Department of Pediatrics, National Hospital Organization Chiba-East Hospital, Chiba, Japan
| | - Anna Kobayashi
- Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Kofu, Japan
| | - Eriko Tanaka
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kazuki Tanaka
- Department of Nephrology, Aichi Children's Health and Medical Center, Obu, Japan
| | - Taketsugu Hama
- Department of Pediatrics, Wakayama Medical University, Wakayama, Japan
| | - Rika Fujimaru
- Department of Pediatrics, Osaka City General Hospital, Izumi, Japan
| | - Saori Miwa
- Department of Pediatrics, The Jikei University School of Medicine, Tokyo, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Natsusmi Yamamura
- Department of Pediatric Nephrology and Metabolism, Osaka Women's and Children's Hospital, Izumi, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Shogo Minamikawa
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Michio Nagata
- Kidney and Vascular Pathology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
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Kume S, Nagasu H, Nangaku M, Nishiyama A, Nakamoto H, Kashihara N. Summary of the 2018 ISN Frontiers Meeting: Kidney Disease and Cardiovascular Disease. Kidney Int Rep 2018. [PMCID: PMC6035142 DOI: 10.1016/j.ekir.2018.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
International Society of Nephrology (ISN) Frontiers meetings build on the success of the ISN Nexus and Forefronts series by bringing together basic scientists, clinicians, and practitioners in a unique setting. This new event was organized to make more innovative science available to a global audience by removing regional barriers in accessing the latest knowledge. The first ISN Frontiers meeting was organized in partnership between the Japanese Society of Nephrology and the Japanese Society for Dialysis Therapy, which was held in Tokyo in February 2018. The meeting focused on the topic “Kidney Disease & Cardiovascular Disease,” which covered a broad range of scientific and clinical fields, including nephrology, cardiovascular diseases, dialysis, transplantation, chronic kidney disease (CKD)–mineral bone disease (MBD), diabetes, pediatric nephrology, nutrition, pharmacology, and nursing. A total of 1584 active physicians and scientists from 64 countries attended the meeting, and a number of leading physician scientists from different and related disciplines of clinical and basic research described and reviewed recent discoveries. This report summarizes the main highlights of the meeting lectures.
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Affiliation(s)
- Shinji Kume
- Department of Medicine, Shiga University of Medical Science, Shiga, Japan
- Correspondence: Shinji Kume, Department of Medicine, Shiga University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga 520-2192, Japan.
| | - Hajime Nagasu
- Department of Nephrology and Hypertension, Kawasaki Medical School, Okayama, Japan
| | - Masaomi Nangaku
- Department of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - Akira Nishiyama
- Department of Pharmacology, Kagawa University, Kagawa, Japan
| | - Hidetomo Nakamoto
- Department of General Internal Medicine, Saitama Medical University, Saitama, Japan
| | - Naoki Kashihara
- Department of Nephrology and Hypertension, Kawasaki Medical School, Okayama, Japan
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Horinouchi T, Nozu K, Yamamura T, Minamikawa S, Omori T, Nakanishi K, Fujimura J, Ashida A, Kitamura M, Kawano M, Shimabukuro W, Kitabayashi C, Imafuku A, Tamagaki K, Kamei K, Okamoto K, Fujinaga S, Oka M, Igarashi T, Miyazono A, Sawanobori E, Fujimaru R, Nakanishi K, Shima Y, Matsuo M, Ye MJ, Nozu Y, Morisada N, Kaito H, Iijima K. Detection of Splicing Abnormalities and Genotype-Phenotype Correlation in X-linked Alport Syndrome. J Am Soc Nephrol 2018; 29:2244-2254. [PMID: 29959198 DOI: 10.1681/asn.2018030228] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/23/2018] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND X-linked Alport syndrome (XLAS) is a progressive hereditary nephropathy caused by mutations in the COL4A5 gene. Genotype-phenotype correlation in male XLAS is relatively well established; relative to truncating mutations, nontruncating mutations exhibit milder phenotypes. However, transcript comparison between XLAS cases with splicing abnormalities that result in a premature stop codon and those with nontruncating splicing abnormalities has not been reported, mainly because transcript analysis is not routinely conducted in patients with XLAS. METHODS We examined transcript expression for all patients with suspected splicing abnormalities who were treated at one hospital between January of 2006 and July of 2017. Additionally, we recruited 46 males from 29 families with splicing abnormalities to examine genotype-phenotype correlation in patients with truncating (n=21, from 14 families) and nontruncating (n=25, from 15 families) mutations at the transcript level. RESULTS We detected 41 XLAS families with abnormal splicing patterns and described novel XLAS atypical splicing patterns (n=14) other than exon skipping caused by point mutations in the splice consensus sequence. The median age for developing ESRD was 20 years (95% confidence interval, 14 to 23 years) among patients with truncating mutations and 29 years (95% confidence interval, 25 to 40 years) among patients with nontruncating mutations (P=0.001). CONCLUSIONS We report unpredictable atypical splicing in the COL4A5 gene in male patients with XLAS and reveal that renal prognosis differs significantly for patients with truncating versus nontruncating splicing abnormalities. Our results suggest that splicing modulation should be explored as a therapy for XLAS with truncating mutations.
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Affiliation(s)
- Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan;
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shogo Minamikawa
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takashi Omori
- Clinical and Translational Research Center, Kobe University Hospital, Kobe, Japan
| | - Keita Nakanishi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Junya Fujimura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Akira Ashida
- Department of Pediatrics, Osaka Medical College, Osaka, Japan
| | - Mineaki Kitamura
- Department of Nephrology, Nagasaki University Hospital, Nagasaki, Japan
| | - Mitsuhiro Kawano
- Department of Rheumatology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Wataru Shimabukuro
- Department of Pediatrics, Japan Community Health Care Organization Kyushu Hospital, Sapporo, Hokkaido, Japan
| | - Chizuko Kitabayashi
- Department of Nephrology and Hypertension, Osaka City General Hospital, Osaka, Japan
| | - Aya Imafuku
- Department of Nephrology, Toranomon Hospital, Tokyo, Japan
| | - Keiichi Tamagaki
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Koichi Kamei
- Division of Nephrology and Rheumatology, National Center for Child Health and Development, Tokyo, Japan
| | - Kenjirou Okamoto
- Department of Urology, Ehime Prefectural Central Hospital, Ehime, Japan
| | - Shuichiro Fujinaga
- Division of Nephrology, Saitama Children's Medical Center, Saitama, Japan
| | - Masafumi Oka
- Department of Pediatrics, Faculty of Medicine Saga University, Saga, Japan
| | - Toru Igarashi
- Department of Pediatrics, Nippon Medical School, Tokyo, Japan
| | - Akinori Miyazono
- Department of Pediatrics, Faculty of Medicine Kagoshima University, Kagoshima, Japan
| | - Emi Sawanobori
- Department of Pediatrics, University of Yamanashi, Yamanashi, Japan
| | - Rika Fujimaru
- Department of Pediatrics, Osaka General Hospital, Osaka, Japan
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Yuko Shima
- Department of Pediatrics, Wakayama Medical University, Wakayama, Japan; and
| | - Masafumi Matsuo
- Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan
| | - Ming Juan Ye
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yoshimi Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroshi Kaito
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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Omachi K, Kamura M, Teramoto K, Kojima H, Yokota T, Kaseda S, Kuwazuru J, Fukuda R, Koyama K, Matsuyama S, Motomura K, Shuto T, Suico MA, Kai H. A Split-Luciferase-Based Trimer Formation Assay as a High-throughput Screening Platform for Therapeutics in Alport Syndrome. Cell Chem Biol 2018. [PMID: 29526710 DOI: 10.1016/j.chembiol.2018.02.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Alport syndrome is a hereditary glomerular disease caused by mutation in type IV collagen α3-α5 chains (α3-α5(IV)), which disrupts trimerization, leading to glomerular basement membrane degeneration. Correcting the trimerization of α3/α4/α5 chain is a feasible therapeutic approach, but is hindered by lack of information on the regulation of intracellular α(IV) chain and the absence of high-throughput screening (HTS) platforms to assess α345(IV) trimer formation. Here, we developed sets of split NanoLuc-fusion α345(IV) proteins to monitor α345(IV) trimerization of wild-type and clinically associated mutant α5(IV). The α345(IV) trimer assay, which satisfied the acceptance criteria for HTS, enabled the characterization of intracellular- and secretion-dependent defects of mutant α5(IV). Small interfering RNA-based and chemical screening targeting the ER identified several chemical chaperones that have potential to promote α345(IV) trimer formation. This split luciferase-based trimer formation assay is a functional HTS platform that realizes the feasibility of targeting α345(IV) trimers to treat Alport syndrome.
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Affiliation(s)
- Kohei Omachi
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan; Program for Leading Graduate School "HIGO (Health Life Science: Interdisciplinary and Glocal Oriented) Program", Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan
| | - Misato Kamura
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan; Program for Leading Graduate School "HIGO (Health Life Science: Interdisciplinary and Glocal Oriented) Program", Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan
| | - Keisuke Teramoto
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan; Program for Leading Graduate School "HIGO (Health Life Science: Interdisciplinary and Glocal Oriented) Program", Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan
| | - Haruka Kojima
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan
| | - Tsubasa Yokota
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan
| | - Shota Kaseda
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan; Program for Leading Graduate School "HIGO (Health Life Science: Interdisciplinary and Glocal Oriented) Program", Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan
| | - Jun Kuwazuru
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan
| | - Ryosuke Fukuda
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan
| | - Kosuke Koyama
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan
| | - Shingo Matsuyama
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan
| | - Keishi Motomura
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan
| | - Tsuyoshi Shuto
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan
| | - Mary Ann Suico
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan.
| | - Hirofumi Kai
- Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan; Program for Leading Graduate School "HIGO (Health Life Science: Interdisciplinary and Glocal Oriented) Program", Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto City 862-0973, Kumamoto, Japan.
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Gettelfinger JD, Dahl JP. Syndromic Hearing Loss: A Brief Review of Common Presentations and Genetics. J Pediatr Genet 2018; 7:1-8. [PMID: 29441214 PMCID: PMC5809162 DOI: 10.1055/s-0037-1617454] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 11/29/2017] [Indexed: 02/07/2023]
Abstract
Congenital hearing loss is one of the most common birth defects worldwide, with around 1 in 500 people experiencing some form of severe hearing loss. While over 400 different syndromes involving hearing loss have been described, it is important to be familiar with a wide range of syndromes involving hearing loss so an early diagnosis can be made and early intervention can be pursued to maximize functional hearing and speech-language development in the setting of verbal communication. This review aims to describe the presentation and genetics for some of the most frequently occurring syndromes involving hearing loss, including neurofibromatosis type 2, branchio-oto-renal syndrome, Treacher Collins syndrome, Stickler syndrome, Waardenburg syndrome, Pendred syndrome, Jervell and Lange-Nielsen syndrome, Usher syndromes, Refsum disease, Alport syndrome, MELAS, and MERRF.
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Affiliation(s)
- John D. Gettelfinger
- Department of Otolaryngology – Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - John P. Dahl
- Department of Otolaryngology – Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, Indiana, United States
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49
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Urinary epidermal growth factor as a prognostic marker for the progression of Alport syndrome in children. Pediatr Nephrol 2018; 33:1731-1739. [PMID: 29948307 PMCID: PMC6132884 DOI: 10.1007/s00467-018-3988-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/21/2018] [Accepted: 05/25/2018] [Indexed: 11/21/2022]
Abstract
BACKGROUND Alport syndrome is a rare hereditary kidney disease manifested with progressive renal failure. Considerable variation exists in terms of disease progression among patients with Alport syndrome. Identification of patients at high risk of rapid progression remains an unmet need. Urinary epidermal growth factor (uEGF) has been shown to be independently associated with risk of progression to adverse kidney outcome in multiple independent adult chronic kidney disease (CKD) cohorts. In this study, we aim to assess if uEGF is associated with kidney impairment and its prognostic value for children with Alport syndrome. METHODS One hundred and seventeen pediatric patients with Alport syndrome and 146 healthy children (3-18 years old) were included in this study. uEGF was measured in duplicates in baseline urine samples using ELISA (R&D) and concentration was normalized by urine creatinine (uEGF/Cr). In patients with longitudinal follow-up data (n = 38), progression was defined as deteriorated kidney function (CKD stage increase) during follow-up period (follow-up length is about 31 months in average). The association of baseline uEGF/Cr level with estimated glomerular filtration rate (eGFR) slope and Alport syndrome patients' progression to a more advanced CKD stage during the follow-up period was used to evaluate the prognostic value of the marker. RESULTS We found that uEGF/creatinine (uEGF/Cr) decreases with age in pediatric patients with Alport syndrome with a significantly faster rate than in healthy children of the same age group. uEGF/Cr is significantly correlated with eGFR (r = 0.75, p < 0.001), after adjustment for age. In 38 patients with longitudinal follow-up, we observed a significant correlation between uEGF/Cr and eGFR slope (r = 0.58, p < 0.001). Patients with lower uEGF/Cr level were at increased risk of progression to a higher CKD stage. uEGF/Cr was able to distinguish progressors from non-progressors with an AUC of 0.88, versus 0.77 by eGFR and 0.81 by 24-h urinary protein (24-h UP). CONCLUSIONS Our study suggests that uEGF/Cr is a promising biomarker for accelerated kidney function decline in pediatric patients with Alport syndrome. It may help to identify patients at high risk of progression for targeted clinical care and improve the patients' stratification in interventional trials.
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50
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Chu CP, Hokamp JA, Cianciolo RE, Dabney AR, Brinkmeyer-Langford C, Lees GE, Nabity MB. RNA-seq of serial kidney biopsies obtained during progression of chronic kidney disease from dogs with X-linked hereditary nephropathy. Sci Rep 2017; 7:16776. [PMID: 29196624 PMCID: PMC5711945 DOI: 10.1038/s41598-017-16603-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 10/25/2017] [Indexed: 12/24/2022] Open
Abstract
Dogs with X-linked hereditary nephropathy (XLHN) have a glomerular basement membrane defect that leads to progressive juvenile-onset renal failure. Their disease is analogous to Alport syndrome in humans, and they also serve as a good model of progressive chronic kidney disease (CKD). However, the gene expression profile that affects progression in this disease has only been partially characterized. To help fill this gap, we used RNA sequencing to identify differentially expressed genes (DEGs), over-represented pathways, and upstream regulators that contribute to kidney disease progression. Total RNA from kidney biopsies was isolated at 3 clinical time points from 3 males with rapidly-progressing CKD, 3 males with slowly-progressing CKD, and 2 age-matched controls. We identified 70 DEGs by comparing rapid and slow groups at specific time points. Based on time course analysis, 1,947 DEGs were identified over the 3 time points revealing upregulation of inflammatory pathways: integrin signaling, T cell activation, and chemokine and cytokine signaling pathways. T cell infiltration was verified by immunohistochemistry. TGF-β1 was identified as the primary upstream regulator. These results provide new insights into the underlying molecular mechanisms of disease progression in XLHN, and the identified DEGs can be potential biomarkers and therapeutic targets translatable to all CKDs.
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Affiliation(s)
- Candice P Chu
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Jessica A Hokamp
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Rachel E Cianciolo
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Alan R Dabney
- Department of Statistics, College of Science, Texas A&M University, College Station, TX, USA
| | - Candice Brinkmeyer-Langford
- Department of Veterinary Integrative Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - George E Lees
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Mary B Nabity
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA.
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