51
|
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.
Collapse
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
| |
Collapse
|
52
|
Daso RE, Banerjee IA. Self-Assembled Peptide-Based Biocomposites for Near-Infrared Light Triggered Drug Release to Tumor Cells. Biotechnol J 2020; 15:e2000128. [PMID: 32845561 DOI: 10.1002/biot.202000128] [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: 05/23/2020] [Revised: 07/21/2020] [Indexed: 11/11/2022]
Abstract
Peptide-based nanomaterials are increasingly gaining popularity due to their specificity, biocompatibility, and biodegradability. In this work, a new multi-layered peptide-based biocomposite for targeting MCF-7 breast cancer cells is developed. The amphipathic Fluorenylmethyloxycarbonyl (Fmoc)-Leu-Ser peptide is synthesized, which is conjugated to a tumor-targeting peptide sequence Gly-Cys-Gly-Asn-Ser to form Fmoc-L-S-G-C-G-N-S (FLS) assemblies. To the FLS assemblies, gold nanorods are then attached to develop drug delivery vehicles (DDVs). The DDVs are entrapped with the anti-cancer drug fulvestrant. Entrapment efficiency is found to be 50.6%. Release studies indicate that irradiating the gold nanorod bound DDVs at NIR wavelength (785 nm) increases drug release by fourfold compared to assemblies that are not irradiated. These results also show higher cytotoxicity and lower cell invasion due to photo-triggered drug release. Furthermore, distinct actin cytoskeletal changes are observed. Such novel peptide-based gold nanorod bound DDVs demonstrate potential in dual targeting of MCF-7 breast cancer cells.
Collapse
Affiliation(s)
- Rachel E Daso
- Department of Chemistry, Fordham University, 441 E. Fordham Road, Bronx, NY, 10458, USA
| | - Ipsita A Banerjee
- Department of Chemistry, Fordham University, 441 E. Fordham Road, Bronx, NY, 10458, USA
| |
Collapse
|
53
|
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]
|
54
|
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: 57] [Impact Index Per Article: 14.3] [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.
Collapse
Affiliation(s)
- Clifford E Kashtan
- Pediatric Nephrology, University of Minnesota Medical School, Minneapolis, MN.
| |
Collapse
|
55
|
Torra R, Furlano M. New therapeutic options for Alport syndrome. Nephrol Dial Transplant 2020; 34:1272-1279. [PMID: 31190059 DOI: 10.1093/ndt/gfz131] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 05/31/2019] [Indexed: 12/12/2022] Open
Abstract
Alport syndrome (AS) is the most frequent inherited kidney disease after autosomal dominant polycystic kidney disease. It has three different patterns of inheritance-autosomal dominant, autosomal recessive and X-linked-which in part explains the wide spectrum of disease, ranging from isolated microhaematuria to end-stage renal disease early in life. The search for a treatment for AS is being pursued vigorously, not only because of the obvious unmet need but also because AS is a rare disease and any drug approved will have an orphan drug designation with its various benefits. Moreover, AS patients are quite young with very few comorbidities, which facilitates clinical trials. This review identifies the particularities of each pattern of inheritance but focuses mainly on new drugs or therapeutic targets for the disease. Most treatment-related investigations are directed not at the main abnormality in AS, namely collagen IV composition, but rather at the associated inflammation and fibrosis. Thus, AS may serve as a proof of concept for numerous drugs of potential value in many diseases that cause chronic kidney disease.
Collapse
Affiliation(s)
- Roser Torra
- Inherited Renal Disorders, Nephrology Department, Fundació Puigvert, REDINREN, IIB Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Mónica Furlano
- Inherited Renal Disorders, Nephrology Department, Fundació Puigvert, REDINREN, IIB Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| |
Collapse
|
56
|
How to resolve confusion in the clinical setting for the diagnosis of heterozygous COL4A3 or COL4A4 gene variants? Discussion and suggestions from nephrologists. Clin Exp Nephrol 2020; 24:651-656. [PMID: 32232700 PMCID: PMC7371658 DOI: 10.1007/s10157-020-01880-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 03/17/2020] [Indexed: 12/22/2022]
Abstract
Both thin basement membrane nephropathy (TBMN) and autosomal dominant Alport syndrome (ADAS) are types of hereditary nephritis resulting from heterozygous mutations in COL4A3 or COL4A4 genes. Although TBMN is characterized by hematuria and thinning of the glomerular basement membrane (GBM) with excellent renal prognosis, some patients develop end-stage renal disease (ESRD) later in life. In contrast, although AS is characterized by progressive nephropathy with lamellation of the GBM, there are some patients diagnosed with ADAS from a family history of ESRD but who only suffer from hematuria with GBM thinning. These findings indicate a limitation in distinction between TBMN and ADAS. Diagnosis of AS is significant because it facilitates careful follow-up and early treatment, whereas diagnosis of TBMN can underestimate the risk of ESRD. However, some experts are against using the term ADAS as the phenotypes of heterozygous variants vary from no urinary abnormality to ESRD, even between family members with the same mutations, indicating that unknown secondary factors may play a large role in the disease severity. These diagnostic difficulties result in significant confusion in clinical settings. Moreover, recent studies revealed that the number of patients with chronic kidney disease caused by these gene mutations is far higher than previously thought. The aim of this article is to review differing opinions regarding the diagnosis of heterozygous COL4A3 or COL4A4 variants, and to highlight the importance for nephrologists to recognize this disease, and the importance of the need to reclassify this disease to minimize the current confusion.
Collapse
|
57
|
Autosomal dominant Alport syndrome due to a COL4A4 mutation with an additional ESPN variant detected by whole-exome analysis. CEN Case Rep 2019; 9:59-64. [PMID: 31677115 DOI: 10.1007/s13730-019-00429-w] [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: 07/09/2019] [Accepted: 10/20/2019] [Indexed: 10/25/2022] Open
Abstract
Alport syndrome (AS) is a rare hereditary disease that presents with chronic kidney disease and sensorineural hearing loss, and is diagnosed by its clinical features, pathological features on renal tissue, and mode of inheritance. We report a woman in her 20 s who exhibited persistent haematuria with normal renal function and sensorineural hearing loss. Her family members exhibited the same clinical findings among three generations and were suspected of having autosomal dominant AS (ADAS). Renal biopsy showed minor glomerular abnormalities on light microscopy and extensive thinning of the glomerular basement membrane on electron microscopy. Whole-exome analysis revealed a known COL4A4 (type IV collagen α4) mutation (c. 2510 G > C: p. Gly837Ala). Two pedigrees with the same variant have been reported previously, one as ADAS and the other as autosomal recessive AS. However, these two cases exhibited no sensorineural hearing loss. The analysis in the present case revealed another missense variant in ESPN (Espin), an actin-bundling protein, which is a causative gene for sensorineural hearing loss. Although the pathophysiological significance of this novel missense variant needs to be clarified, computational analysis predicted that the variant creates a new phosphorylation site for protein kinase C. Our case suggests a possible association of hereditary sensorineural hearing loss with ADAS. Whole-exome analysis should be considered to diagnose hereditary and multiple-organ disorders.
Collapse
|
58
|
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.
Collapse
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
| |
Collapse
|
59
|
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.
Collapse
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
| |
Collapse
|
60
|
Yang C, Song Y, Chen Z, Yuan X, Chen X, Ding G, Guan Y, McGrath M, Song C, Tong Y, Wang H. A Nonsense Mutation in COL4A4 Gene Causing Isolated Hematuria in Either Heterozygous or Homozygous State. Front Genet 2019; 10:628. [PMID: 31312213 PMCID: PMC6614519 DOI: 10.3389/fgene.2019.00628] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/17/2019] [Indexed: 01/15/2023] Open
Abstract
Alport syndrome (AS) is a hereditary nephropathy characterized by glomerular basement membrane lesions. AS shows a relatively rare entity with autosomal dominant gene mutation (accounts for less than 5% of AS cases) and is widely believed to be a consequence of heterozygous variants in the COL4A3 and COL4A4 genes. Until now, there have been no reports of homozygous variants in genes in AS patients, and it is scarce to detect both homozygous and heterozygous variants in a single AS pedigree. We performed genetic analysis by exome sequencing (exome-seq) in a Chinese family with AS and found four individuals harboring the COL4A4 c.4599T > G variant, a novel COL4A4 nonsense mutation that gains stop codon and results in a truncated protein. The proband and her two siblings were determined to be heterozygous, whereas their mother was homozygous. The proband satisfied the criteria for the diagnosis of AS, which included clinical manifestations of microscopic hematuria and proteinuria, and pathological features of the glomerular basement membrane (GBM), including irregular thickening and splitting. However, the other three individuals who were homozygous or heterozygous for the variant exhibited mild clinical features with isolated microscopic hematuria. In summary, we identified a novel pathogenic variant in either the heterozygous or homozygous state of the COL4A4 gene in a Chinese family with AS. Our results also suggest that the severity of clinical manifestations may not be entirely attributed to by the COL4A4 genetic variant itself in patients.
Collapse
Affiliation(s)
- Cheng Yang
- Renal Department, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yuan Song
- Renal Department, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zhaowei Chen
- Renal Department, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xiaohan Yuan
- Renal Department, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xinhua Chen
- Renal Department, Renmin Hospital of Wuhan University, Wuhan, China
| | - Guohua Ding
- Renal Department, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yang Guan
- Ultrastructure Center, Renmin Hospital of Wuhan University, Wuhan, China
| | - Mary McGrath
- Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Chunhua Song
- Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Yongqing Tong
- Department of Laboratory Science, Renmin Hospital of Wuhan University, Wuhan, China
| | - Huiming Wang
- Renal Department, Renmin Hospital of Wuhan University, Wuhan, China
| |
Collapse
|
61
|
Gribouval O, Boyer O, Hummel A, Dantal J, Martinez F, Sberro-Soussan R, Etienne I, Chauveau D, Delahousse M, Lionet A, Allard J, Pouteil Noble C, Tête MJ, Heidet L, Antignac C, Servais A. Identification of genetic causes for sporadic steroid-resistant nephrotic syndrome in adults. Kidney Int 2019; 94:1013-1022. [PMID: 30348286 DOI: 10.1016/j.kint.2018.07.024] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/18/2018] [Accepted: 07/12/2018] [Indexed: 01/15/2023]
Abstract
Monogenic forms of Steroid-Resistant Nephrotic Syndrome (SRNS) have been widely characterized, but genetic screening paradigms preferentially address congenital, infantile onset, and familial cases. Our aim was to characterize the distribution of disease-causing gene mutations in adults with sporadic SRNS or focal segmental glomerulosclerosis (FSGS). We selected adult patients with non-syndromic, biopsy-proven FSGS or SRNS in the absence of known family history. Strict clinical criteria included lack of response to glucocorticoids and cyclosporine, and no recurrence after kidney transplantation. Mutations in SRNS genes were detected using a targeted gene panel. Sixteen of 135 tested participants (11.8%) carried pathogenic mutations in monogenic SRNS genes, and 14 others (10.4%) carried two APOL1 high-risk alleles. Autosomal recessive disease was diagnosed in 5 participants, autosomal dominant disease in 9, and X-linked disease in 2. Four participants carried a de novo heterozygous mutation. Among the 16 participants with identified mutations in monogenic SNRS genes, 7 (43.7%) had type IV collagen mutations. Mutations in monogenic SNRS genes were identified primarily in participants with proteinuria onset before 25 years of age, while the age at disease onset was variable in those with APOL1 high-risk genotype. Mean age at diagnosis was lower and renal survival was worse in participants with identified mutations in SNRS genes than in those without mutations. We found a significant rate of pathogenic mutations in adults with SRNS, with Type IV collagen mutations being the most frequent. These findings may have immediate impact on clinical practice.
Collapse
Affiliation(s)
- Olivier Gribouval
- Inserm U1163, Imagine Institute, Paris Descartes University, Paris, France
| | - Olivia Boyer
- Inserm U1163, Imagine Institute, Paris Descartes University, Paris, France; Pediatric Nephrology, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, Paris, France
| | - Aurélie Hummel
- Inserm U1163, Imagine Institute, Paris Descartes University, Paris, France; Adult Nephrology & Transplantation, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, Paris, France
| | | | - Frank Martinez
- Adult Nephrology & Transplantation, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, Paris, France
| | - Rebecca Sberro-Soussan
- Adult Nephrology & Transplantation, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, Paris, France
| | - Isabelle Etienne
- Nephrology Department, Hôpital de Bois-Guillaume, CHU Rouen, Rouen, France
| | - Dominique Chauveau
- Department of Nephrology and Organ Transplantation, CHU Rangueil, Toulouse, France
| | | | - Arnaud Lionet
- Nephrology Department, Hôpital Huriez, CHU Lille, Lille, France
| | | | - Claire Pouteil Noble
- Nephrology-Transplantation Department, Hôpital Edouard Herriot, Lyon I University, Lyon, France
| | - Marie-Josèphe Tête
- Inserm U1163, Imagine Institute, Paris Descartes University, Paris, France
| | - Laurence Heidet
- Inserm U1163, Imagine Institute, Paris Descartes University, Paris, France; Pediatric Nephrology, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, Paris, France; Genetic Department, Necker Hospital, APHP, Paris, France
| | - Corinne Antignac
- Inserm U1163, Imagine Institute, Paris Descartes University, Paris, France; Genetic Department, Necker Hospital, APHP, Paris, France.
| | - Aude Servais
- Inserm U1163, Imagine Institute, Paris Descartes University, Paris, France; Adult Nephrology & Transplantation, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, Paris, France.
| |
Collapse
|
62
|
Shima N, Hayami N, Mizuno H, Kawada M, Sekine A, Sumida K, Hiramatsu R, Yamanouchi M, Hasegawa E, Suwabe T, Hoshino J, Sawa N, Takaichi K, Ohashi K, Fujii T, Minota S, Ubara Y. Arteriovenous fistula-related renal bleeding 5 days after percutaneous renal biopsy. CEN Case Rep 2019; 8:280-284. [PMID: 31214889 PMCID: PMC6820813 DOI: 10.1007/s13730-019-00408-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 06/07/2019] [Indexed: 11/25/2022] Open
Abstract
A 32-year-old Japanese woman was admitted to our hospital for evaluation of microscopic hematuria with a positive family history. Percutaneous renal biopsy was performed under real-time ultrasound guidance using a 16-gauge automated needle and three specimens were obtained. She had no risk factors for hemorrhage. However, macroscopic hematuria developed from 5 days after biopsy and persisted for 4 days. Her Hb decreased markedly from 15.0 to 8.1 g/dL. Enhanced computed tomography revealed urinary tract hematoma, while the early arterial phase showed inflow of contrast medium into the left renal vein from a pseudoaneurysm on a branch left renal artery. Renal transcatheter arterial embolization was performed using platinum microcoils and the arteriovenous fistula was occluded. The patient did not require blood transfusion. Severe renal bleeding that causes urinary tract hematoma usually occurs within 24 h after renal biopsy, but the possibility of late-onset renal bleeding should be kept in mind.
Collapse
Affiliation(s)
- Natsuki Shima
- Nephrology Center, Toranomon Hospital Kajigaya, 1-3-1, Takatsu, Kawasaki, Kanagawa, 212-0015, Japan.,Division of Rheumatology and Clinical Immunology, Department of Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Noriko Hayami
- Nephrology Center, Toranomon Hospital Kajigaya, 1-3-1, Takatsu, Kawasaki, Kanagawa, 212-0015, Japan
| | - Hiroki Mizuno
- Nephrology Center, Toranomon Hospital Kajigaya, 1-3-1, Takatsu, Kawasaki, Kanagawa, 212-0015, Japan
| | - Masahiro Kawada
- Nephrology Center, Toranomon Hospital Kajigaya, 1-3-1, Takatsu, Kawasaki, Kanagawa, 212-0015, Japan
| | - Akinari Sekine
- Nephrology Center, Toranomon Hospital Kajigaya, 1-3-1, Takatsu, Kawasaki, Kanagawa, 212-0015, Japan
| | - Keiichi Sumida
- Nephrology Center, Toranomon Hospital Kajigaya, 1-3-1, Takatsu, Kawasaki, Kanagawa, 212-0015, Japan
| | - Rikako Hiramatsu
- Nephrology Center, Toranomon Hospital Kajigaya, 1-3-1, Takatsu, Kawasaki, Kanagawa, 212-0015, Japan
| | - Masayuki Yamanouchi
- Nephrology Center, Toranomon Hospital Kajigaya, 1-3-1, Takatsu, Kawasaki, Kanagawa, 212-0015, Japan
| | - Eiko Hasegawa
- Nephrology Center, Toranomon Hospital Kajigaya, 1-3-1, Takatsu, Kawasaki, Kanagawa, 212-0015, Japan
| | - Tatsuya Suwabe
- Nephrology Center, Toranomon Hospital Kajigaya, 1-3-1, Takatsu, Kawasaki, Kanagawa, 212-0015, Japan
| | - Junichi Hoshino
- Nephrology Center, Toranomon Hospital Kajigaya, 1-3-1, Takatsu, Kawasaki, Kanagawa, 212-0015, Japan.,Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan
| | - Naoki Sawa
- Nephrology Center, Toranomon Hospital Kajigaya, 1-3-1, Takatsu, Kawasaki, Kanagawa, 212-0015, Japan
| | - Kenmei Takaichi
- Nephrology Center, Toranomon Hospital Kajigaya, 1-3-1, Takatsu, Kawasaki, Kanagawa, 212-0015, Japan.,Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan
| | - Kenichi Ohashi
- Department of Pathology, Toranomon Hospital, Tokyo, Japan.,Department of Pathology, Yokohama City University Hospital Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Takeshi Fujii
- Department of Pathology, Toranomon Hospital, Tokyo, Japan
| | - Seiji Minota
- Division of Rheumatology and Clinical Immunology, Department of Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Yoshifumi Ubara
- Nephrology Center, Toranomon Hospital Kajigaya, 1-3-1, Takatsu, Kawasaki, Kanagawa, 212-0015, Japan. .,Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan.
| |
Collapse
|
63
|
Shang S, Peng F, Wang T, Wu X, Li P, Li Q, Chen XM. Genotype-phenotype correlation and prognostic impact in Chinese patients with Alport Syndrome. Mol Genet Genomic Med 2019; 7:e00741. [PMID: 31144478 PMCID: PMC6625365 DOI: 10.1002/mgg3.741] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 04/12/2019] [Accepted: 04/15/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Alport Syndrome (AS) is a progressive hereditary glomerular disease. It is often accompanied by sensorineural hearing loss and ocular abnormalities and can sometimes develop into end stage renal disease (ESRD), which is caused by mutations in the genes encoding the collagen type IV family of proteins. METHODS This study analyzed the association between the clinical data of seven AS families and genes and the disease progression of different mutation types, including COL4A3 (OMIM 120070),COL4A4 (OMIM 120131), and COL4A5 (OMIM303630). RESULTS A total of six new pathogenic mutation sites, one complex heterozygous mutation at COL4A3, and a combined mutation of COL4A5 and INF2 (OMIM 610982) were identified in this study. It was revealed that the clinical manifestations of X-linked AS caused by mutations in the COL4A5 gene were more severe in males than in females. In addition, the difference in patient phenotype can be attributed to the location of gene mutations affecting the protein domain or functional domain. Our data suggested that the gene deletion and nonsense mutations had a high risk for progression to ESRD. CONCLUSION Our results revealed the spectrum of type IV collagen genes, which contribute to the enrichment of database resources and has important implications in the diagnosis, prognosis, and guiding treatment of AS.
Collapse
Affiliation(s)
- Shunlai Shang
- Department of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Chinese PLA General Hospital, Medical School of Chinese PLA, Chinese PLA Institute of Nephrology, Beijing, China
| | - Fei Peng
- Department of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Chinese PLA General Hospital, Medical School of Chinese PLA, Chinese PLA Institute of Nephrology, Beijing, China.,School of Medicine, Nankai University, Tianjin, China
| | - Tao Wang
- Department of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Chinese PLA General Hospital, Medical School of Chinese PLA, Chinese PLA Institute of Nephrology, Beijing, China
| | - Xiaoyuan Wu
- Department of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Chinese PLA General Hospital, Medical School of Chinese PLA, Chinese PLA Institute of Nephrology, Beijing, China
| | - Ping Li
- Department of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Chinese PLA General Hospital, Medical School of Chinese PLA, Chinese PLA Institute of Nephrology, Beijing, China
| | - Qinggang Li
- Department of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Chinese PLA General Hospital, Medical School of Chinese PLA, Chinese PLA Institute of Nephrology, Beijing, China
| | - Xiang M Chen
- Department of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Chinese PLA General Hospital, Medical School of Chinese PLA, Chinese PLA Institute of Nephrology, Beijing, China
| |
Collapse
|
64
|
Zhao X, Chen C, Wei Y, Zhao G, Liu L, Wang C, Zhang J, Kong X. Novel mutations of COL4A3, COL4A4, and COL4A5 genes in Chinese patients with Alport Syndrome using next generation sequence technique. Mol Genet Genomic Med 2019; 7:e653. [PMID: 30968591 PMCID: PMC6565573 DOI: 10.1002/mgg3.653] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 01/23/2019] [Accepted: 03/04/2019] [Indexed: 01/01/2023] Open
Abstract
Background Alport syndrome (AS) is an inherited progressive renal disease caused by mutations in COL4A3, COL4A4, and COL4A5 genes. The large sizes of these genes and the absence of mutation hot spots have complicated mutational analysis by routine PCR‐based approaches. In recent years, the development of next‐generation sequencing (NGS) has made possible the time‐ and cost‐effective and accurate analysis of the three genes in a single step. Methods Here, we analyze COL4A3, COL4A4, and COL4A5 simultaneously in 29 AS patients using NGS. Candidate mutations were validated by classic Sanger sequencing and Real‐time PCR. Results Twenty two new mutations and 10 known mutations were detected. Of those novel mutations, 18, 3, and 1 mutations were detected in COL4A5, COL4A4, and COL4A3, respectively. Twenty six patients showed X‐linked inheritance, one showed autosomal recessive inheritance and two showed digenic inheritance (DI). Conclusion A comparison of the clinical manifestations caused by different types of mutations in COL4A5 suggested that large fragment mutations are relatively more severe than the other missense mutations and AS by some mutations may show inter‐ and intra‐familial phenotypic variability. It is important to consider these transmission patterns in the clinical evaluation according to the results of genetic testing, especially for DI. Twenty two new mutations can expand the genotypic spectrum of AS.
Collapse
Affiliation(s)
- Xuechao Zhao
- Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Henan Engineering Research Center for Gene Editing of Human Genetic Disease, Erqi District, Zhengzhou, China
| | - Chen Chen
- Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Henan Engineering Research Center for Gene Editing of Human Genetic Disease, Erqi District, Zhengzhou, China
| | - Yanfu Wei
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Research Institute of Nephrology, Zhengzhou University, Zhengzhou, China
| | - Ganye Zhao
- Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Henan Engineering Research Center for Gene Editing of Human Genetic Disease, Erqi District, Zhengzhou, China
| | - Lina Liu
- Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Henan Engineering Research Center for Gene Editing of Human Genetic Disease, Erqi District, Zhengzhou, China
| | - Conghui Wang
- Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Henan Engineering Research Center for Gene Editing of Human Genetic Disease, Erqi District, Zhengzhou, China
| | - Junjun Zhang
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Research Institute of Nephrology, Zhengzhou University, Zhengzhou, China
| | - Xiangdong Kong
- Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Henan Engineering Research Center for Gene Editing of Human Genetic Disease, Erqi District, Zhengzhou, China
| |
Collapse
|
65
|
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.
Collapse
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
| |
Collapse
|
66
|
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: 23] [Impact Index Per Article: 4.6] [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.
Collapse
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
| |
Collapse
|
67
|
Kashtan CE. Renal transplantation in patients with Alport syndrome: patient selection, outcomes, and donor evaluation. Int J Nephrol Renovasc Dis 2018; 11:267-270. [PMID: 30410383 PMCID: PMC6198874 DOI: 10.2147/ijnrd.s150539] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Alport syndrome is an inherited disorder of basement membrane collagen IV that frequently results in end-stage renal disease. Patients with Alport syndrome who undergo renal transplantation have generally excellent outcomes. Posttransplant antiglomerular basement membrane nephritis is a rare complication of renal transplantation for Alport syndrome. Because Alport syndrome is a genetic disorder, potential related donors must be carefully evaluated in order to minimize harm.
Collapse
Affiliation(s)
- Clifford E Kashtan
- Division of Nephrology, Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN 55454, USA,
| |
Collapse
|
68
|
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.
Collapse
|
69
|
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.
Collapse
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
| |
Collapse
|
70
|
Zhang Y, Ding J. Renal, auricular, and ocular outcomes of Alport syndrome and their current management. Pediatr Nephrol 2018; 33:1309-1316. [PMID: 28864840 DOI: 10.1007/s00467-017-3784-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 08/01/2017] [Accepted: 08/10/2017] [Indexed: 01/27/2023]
Abstract
Alport syndrome is a hereditary glomerular basement membrane disease caused by mutations in the COL4A3/4/5 genes encoding the type IV collagen alpha 3-5 chains. Most cases of Alport syndrome are inherited as X-linked dominant, and some as autosomal recessive or autosomal dominant. The primary manifestations are hematuria, proteinuria, and progressive renal failure, whereas some patients present with sensorineural hearing loss and ocular abnormalities. Renin-angiotensin-aldosterone system blockade is proven to delay the onset of renal failure by reducing proteinuria. Renal transplantation is a curative treatment for patients who have progressed to end-stage renal disease. However, only supportive measures can be used to improve hearing loss and visual loss. Although both stem cell therapy and gene therapy aim to repair the basement membrane defects, technical difficulties require more research in Alport mice before clinical studies. Here, we review the renal, auricular, and ocular manifestations and outcomes of Alport syndrome and their current management.
Collapse
Affiliation(s)
- Yanqin Zhang
- Pediatric Department, Peking University First Hospital, Beijing, China
| | - Jie Ding
- Pediatric Department, Peking University First Hospital, Beijing, China.
| |
Collapse
|
71
|
Ding W, Yousefi K, Goncalves S, Goldstein BJ, Sabater AL, Kloosterboer A, Ritter P, Lambert G, Mendez AJ, Shehadeh LA. Osteopontin deficiency ameliorates Alport pathology by preventing tubular metabolic deficits. JCI Insight 2018; 3:94818. [PMID: 29563333 PMCID: PMC5926939 DOI: 10.1172/jci.insight.94818] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 02/09/2018] [Indexed: 12/31/2022] Open
Abstract
Alport syndrome is a rare hereditary renal disorder with no etiologic therapy. We found that osteopontin (OPN) is highly expressed in the renal tubules of the Alport mouse and plays a causative pathological role. OPN genetic deletion ameliorated albuminuria, hypertension, tubulointerstitial proliferation, renal apoptosis, and hearing and visual deficits in the Alport mouse. In Alport renal tubules we found extensive cholesterol accumulation and increased protein expression of dynamin-3 (DNM3) and LDL receptor (LDLR) in addition to dysmorphic mitochondria with defective bioenergetics. Increased pathological cholesterol influx was confirmed by a remarkably increased uptake of injected DiI-LDL cholesterol by Alport renal tubules, and by the improved lifespan of the Alport mice when crossed with the Ldlr-/- mice with defective cholesterol influx. Moreover, OPN-deficient Alport mice demonstrated significant reduction of DNM3 and LDLR expression. In human renal epithelial cells, overexpressing DNM3 resulted in elevated LDLR protein expression and defective mitochondrial respiration. Our results suggest a potentially new pathway in Alport pathology where tubular OPN causes DNM3- and LDLR-mediated enhanced cholesterol influx and impaired mitochondrial respiration.
Collapse
Affiliation(s)
- Wen Ding
- Department of Molecular and Cellular Pharmacology
- Interdisciplinary Stem Cell Institute
| | - Keyvan Yousefi
- Department of Molecular and Cellular Pharmacology
- Interdisciplinary Stem Cell Institute
| | | | | | | | | | | | | | | | - Lina A. Shehadeh
- Interdisciplinary Stem Cell Institute
- Department of Medicine, Division of Cardiology
- Vascular Biology Institute, and
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA
| |
Collapse
|
72
|
Xiang R, Li JJ, Liu JS, Fan LL, Li L, Xia K, Zhang H. Long-term follow-up of an Alport syndrome patient with a novel mutation of COL4A5. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2017; 10:8709-8714. [PMID: 31966729 PMCID: PMC6965389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 05/27/2017] [Indexed: 06/10/2023]
Abstract
BACKGROUND Alport syndrome (AS) is a genetic disease characterized by progressive glomerulonephritis with a high life-time risk for end-stage renal disease (ESRD), sensorineural hearing loss and ocular abnormalities. So far, a lot of mutations were reported in COL4A3, COL4A4 and COL4A5 genes, which are related to AS. METHODS Whole-exome sequencing in combination with AS-related genes filtering strategy was applied to investigate a Chinese AS family. We also employed Sanger sequencing to confirm the family co-segregation. In addition, we also summed up a long-term follow-up data from 2003 to 2016. RESULTS In this study, we have detected a novel insertion mutation (c.348_349insTCCGG/p.G117Sfs×40) of COL4A5, which may lead to a truncated protein in the proband. Sanger sequencing confirmed that this novel mutation was co-segregated with all the family members. The long-term follow-up data showed that the progress of chronic kidney disease become more and more serious in the proband. CONCLUSIONS A novel mutation (c.348_349insTCCGG/p.G117Sfs×40) of COL4A5 was identified in this study. In addition, approximately 15 years long-term follow-up data was provided in this paper. Our study not only expands the spectrum of COL4A5 mutations, but also analysis the progress of AS and fills the knowledge about course and potential further complications and health risks of AS.
Collapse
Affiliation(s)
- Rong Xiang
- The State Key Laboratory of Medical Genetics & School of Life Sciences, Central South UniversityChangsha, China
| | - Jing-Jing Li
- The State Key Laboratory of Medical Genetics & School of Life Sciences, Central South UniversityChangsha, China
| | - Ji-Shi Liu
- Department of Nephrology, The Third Xiangya Hospital of Central South UniversityChangsha, China
| | - Liang-Liang Fan
- The State Key Laboratory of Medical Genetics & School of Life Sciences, Central South UniversityChangsha, China
| | - Lin Li
- Department of Nephrology, The Third Xiangya Hospital of Central South UniversityChangsha, China
| | - Kun Xia
- The State Key Laboratory of Medical Genetics & School of Life Sciences, Central South UniversityChangsha, China
| | - Hao Zhang
- Department of Nephrology, The Third Xiangya Hospital of Central South UniversityChangsha, China
| |
Collapse
|
73
|
Ars E, Torra R. Rare diseases, rare presentations: recognizing atypical inherited kidney disease phenotypes in the age of genomics. Clin Kidney J 2017; 10:586-593. [PMID: 28980669 PMCID: PMC5622904 DOI: 10.1093/ckj/sfx051] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 05/03/2017] [Indexed: 12/11/2022] Open
Abstract
A significant percentage of adults (10%) and children (20%) on renal replacement therapy have an inherited kidney disease (IKD). The new genomic era, ushered in by the next generation sequencing techniques, has contributed to the identification of new genes and facilitated the genetic diagnosis of the highly heterogeneous IKDs. Consequently, it has also allowed the reclassification of diseases and has broadened the phenotypic spectrum of many classical IKDs. Various genetic, epigenetic and environmental factors may explain ‘atypical’ phenotypes. In this article, we examine different mechanisms that may contribute to phenotypic variability and also provide case examples that illustrate them. The aim of the article is to raise awareness, among nephrologists and geneticists, of rare presentations that IKDs may show, to facilitate diagnosis.
Collapse
Affiliation(s)
- Elisabet Ars
- Molecular Biology Laboratory, Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau (IIB-Sant Pau), Universitat Autònoma de Barcelona, REDinREN, Instituto de Investigación Carlos III, Barcelona, Spain
| | - Roser Torra
- Inherited Kidney Disorders, Nephrology Department, Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau (IIB-Sant Pau), Universitat Autònoma de Barcelona, REDinREN, Instituto de Investigación Carlos III, Barcelona, Spain
| |
Collapse
|
74
|
Liu JH, Wei XX, Li A, Cui YX, Xia XY, Qin WS, Zhang MC, Gao EZ, Sun J, Gao CL, Liu FX, Wu QY, Li WW, Liu ZH, Li XJ. Novel mutations in COL4A3, COL4A4, and COL4A5 in Chinese patients with Alport Syndrome. PLoS One 2017; 12:e0177685. [PMID: 28542346 PMCID: PMC5436713 DOI: 10.1371/journal.pone.0177685] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 05/01/2017] [Indexed: 12/18/2022] Open
Abstract
Alport syndrome (AS) is a clinically and genetically heterogeneous, progressive nephropathy caused by mutations in COL4A3, COL4A4, and COL4A5, which encode type IV collagen. The large sizes of these genes and the absence of mutation hot spots have complicated mutational analysis by routine polymerase chain reaction (PCR)-based approaches. Here, in order to design a rapid and effective method for the genetic diagnosis of AS, we developed a strategy by utilizing targeted capture associated with next-generation sequencing (NGS) to analyze COL4A3, COL4A4, and COL4A5 simultaneously in 20 AS patients. All the coding exons and flanking sequences of COL4A3, COL4A4, and COL4A5 from the probands were captured followed by HiSeq 2500 sequencing. Candidate mutations were validated by classic Sanger sequencing and quantitative (q)PCR. Sixteen patients (16/20, 75%) showed X-linked inheritance, and four patients (4/20, 20%) showed autosomal recessive inheritance. None of the individuals had autosomal-dominant AS. Fifteen novel mutations, 6 known mutations, and 2 novel fragment deletions were detected by targeted capture and NGS. Of these novel mutations, 12, 3, and 2 mutations were detected in COL4A5, COL4A4, and COL4A3, respectively. A comparison of the clinical manifestations caused by different types of mutations in COL4A5 suggested that nonsense mutations and glycine substitution by an acidic amino acid are more severe than the other missense mutations. Pathogenic mutations were detected in 20 patients. These novel mutations can expand the genotypic spectrum of AS. Our results demonstrated that targeted capture and NGS technology are effective in the genetic diagnosis of AS.
Collapse
Affiliation(s)
- Jian-Hong Liu
- Institute of Clinical Laboratory Science, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xiu-Xiu Wei
- Binhai Genomics Institute, BGI-Tianjin, BGI-shenzhen, Tianjin, China
| | - Ang Li
- Institute of Clinical Laboratory Science, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Ying-Xia Cui
- Institute of Clinical Laboratory Science, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Xin-Yi Xia
- Institute of Clinical Laboratory Science, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Wei-Song Qin
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Ming-Chao Zhang
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Er-Zhi Gao
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Jun Sun
- Binhai Genomics Institute, BGI-Tianjin, BGI-shenzhen, Tianjin, China
| | - Chun-Lin Gao
- Department of Pediatric Nephrology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Feng-Xia Liu
- Binhai Genomics Institute, BGI-Tianjin, BGI-shenzhen, Tianjin, China
| | - Qiu-Yue Wu
- Institute of Clinical Laboratory Science, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Wei-Wei Li
- Institute of Clinical Laboratory Science, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Zhi-Hong Liu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
- * E-mail: (XJL); (A); (ZHL)
| | - Xiao-Jun Li
- Institute of Clinical Laboratory Science, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
- State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing, China
- * E-mail: (XJL); (A); (ZHL)
| |
Collapse
|
75
|
A functional variant in NEPH3 gene confers high risk of renal failure in primary hematuric glomerulopathies. Evidence for predisposition to microalbuminuria in the general population. PLoS One 2017; 12:e0174274. [PMID: 28334007 PMCID: PMC5363870 DOI: 10.1371/journal.pone.0174274] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 03/06/2017] [Indexed: 01/06/2023] Open
Abstract
Background Recent data emphasize that thin basement membrane nephropathy (TBMN) should not be viewed as a form of benign familial hematuria since chronic renal failure (CRF) and even end-stage renal disease (ESRD), is a possible development for a subset of patients on long-term follow-up, through the onset of focal and segmental glomerulosclerosis (FSGS). We hypothesize that genetic modifiers may explain this variability of symptoms. Methods We looked in silico for potentially deleterious functional SNPs, using very strict criteria, in all the genes significantly expressed in the slit diaphragm (SD). Two variants were genotyped in a cohort of well-studied adult TBMN patients from 19 Greek-Cypriot families, with a homogeneous genetic background. Patients were categorized as “Severe” or “Mild”, based on the presence or not of proteinuria, CRF and ESRD. A larger pooled cohort (HEMATURIA) of 524 patients, including IgA nephropathy patients, was used for verification. Additionally, three large general population cohorts [Framingham Heart Study (FHS), KORAF4 and SAPHIR] were used to investigate if the NEPH3-V353M variant has any renal effect in the general population. Results and conclusions Genotyping for two high-scored variants in 103 TBMN adult patients with founder mutations who were classified as mildly or severely affected, pointed to an association with variant NEPH3-V353M (filtrin). This promising result prompted testing in the larger pooled cohort (HEMATURIA), indicating an association of the 353M variant with disease severity under the dominant model (p = 3.0x10-3, OR = 6.64 adjusting for gender/age; allelic association: p = 4.2x10-3 adjusting for patients’ kinships). Subsequently, genotyping 6,531 subjects of the Framingham Heart Study (FHS) revealed an association of the homozygous 353M/M genotype with microalbuminuria (p = 1.0x10-3). Two further general population cohorts, KORAF4 and SAPHIR confirmed the association, and a meta-analysis of all three cohorts (11,258 individuals) was highly significant (p = 1.3x10-5, OR = 7.46). Functional studies showed that Neph3 homodimerization and Neph3-Nephrin heterodimerization are disturbed by variant 353M. Additionally, 353M was associated with differential activation of the unfolded protein response pathway, when overexpressed in stressed cultured undifferentiated podocyte cells, thus attesting to its functional significance. Genetics and functional studies support a “rare variant-strong effect” role for NEPH3-V353M, by exerting a negative modifier effect on primary glomerular hematuria. Additionally, genetics studies provide evidence for a role in predisposing homozygous subjects of the general population to micro-albuminuria.
Collapse
|
76
|
Focal segmental glomerulosclerosis associated with mitochondrial disease. Clin Nephrol Case Stud 2017; 5:20-25. [PMID: 29043143 PMCID: PMC5438005 DOI: 10.5414/cncs109083] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 01/06/2017] [Indexed: 12/30/2022] Open
Abstract
Primary mitochondrial diseases (MD) are complex, heterogeneous inherited diseases caused by mutations in either the mitochondrial or nuclear DNA. Glomerular diseases in MD have been reported with tRNA mutation m.3243A>G causing a syndrome of mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS). We describe here a case of focal segmental glomerulosclerosis (FSGS) associated with a new tRNA mutation site. A 34-year-old man with a history of living related kidney transplantation, diabetes, hearing loss, and developmental delay presented to the outpatient clinic with complaints of new behavioral difficulties, worsening symptoms, and brain involvement on imaging. Physical examination was remarkable for difficulty hearing, a pattern of dysarthric speech, and cerebellar gait. Laboratory investigations including lactate levels were unremarkable. Based on this set of clinical circumstances, concern for an underlying genetic abnormality was raised. Multiple metabolic tests were unremarkable. Whole exome sequencing revealed a mitochondrial MT-TW tRNA change at position m.5538G>A. Genotype-phenotype correlations are consistent with this tRNA mutation as a cause of his symptoms. To the best of our knowledge, this is the first case describing FSGS-associated MD caused by an m.5538 G>A mutation. Consideration of an underlying MD should be made in patients presenting with deafness, neurologic changes, diabetes, and renal failure.
Collapse
|
77
|
Yokota K, Nozu K, Minamikawa S, Yamamura T, Nakanishi K, Kaneda H, Hamada R, Nozu Y, Shono A, Ninchoji T, Morisada N, Ishimori S, Fujimura J, Horinouchi T, Kaito H, Nakanishi K, Morioka I, Taniguchi-Ikeda M, Iijima K. Female X-linked Alport syndrome with somatic mosaicism. Clin Exp Nephrol 2016; 21:877-883. [DOI: 10.1007/s10157-016-1352-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 10/16/2016] [Indexed: 01/15/2023]
|
78
|
Abstract
Genetic studies of hereditary forms of nephrotic syndrome have identified several proteins that are involved in regulating the permselective properties of the glomerular filtration system. Further extensive research has elucidated the complex molecular basis of the glomerular filtration barrier and clearly established the pivotal role of podocytes in the pathophysiology of glomerular diseases. Podocyte architecture is centred on focal adhesions and slit diaphragms - multiprotein signalling hubs that regulate cell morphology and function. A highly interconnected actin cytoskeleton enables podocytes to adapt in order to accommodate environmental changes and maintain an intact glomerular filtration barrier. Actin-based endocytosis has now emerged as a regulator of podocyte integrity, providing an impetus for understanding the precise mechanisms that underlie the steady-state control of focal adhesion and slit diaphragm components. This Review outlines the role of actin dynamics and endocytosis in podocyte biology, and discusses how molecular heterogeneity in glomerular disorders could be exploited to deliver more rational therapeutic interventions, paving the way for targeted medicine in nephrology.
Collapse
|