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Li Y, Yan X, Luo Z, Fu X, Li Z, Xu Q, Chen J, Yang J, Lu D. Aberrant Splicing of COL4A5 Intronic Variant Contribute to the Pathogenesis of X-Linked Alport Syndrome: A Case Series. Int J Nephrol Renovasc Dis 2024; 17:167-174. [PMID: 38855711 PMCID: PMC11162193 DOI: 10.2147/ijnrd.s459363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Accepted: 05/23/2024] [Indexed: 06/11/2024] Open
Abstract
Introduction X-linked Alport syndrome (XLAS) is caused by pathogenic variants in COL4A5 which lead to abnormalities of the glomerular basement membrane (GBM) structural and is characterized by progressive kidney disease, hearing loss, and ocular abnormalities. The aim of this study was to identify gene mutations in a Chinese family with XLAS by whole-exome sequencing (WES) and verified the pathogenicity of the mutation in vitro experiments. Case Presentation A five-generation pedigree with a total of 49 family members originating from Hainan province of China was investigated in this study. The proband was a 23-year-old male who developed microscopic hematuria, proteinuria and end-stage kidney disease (ESKD) at age 17. WES identified a novel splicing mutation c.321+5G>A of COL4A5, which cause exon skip. Further co-segregation analysis confirmed that this mutation exists in relatives who had renal abnormalities using Sanger sequencing. According to American College of Medical Genetics and Genomics guidelines (ACMG), the mutation was determined to be of uncertain significance (VUS). In vitro splicing experiments have shown that the COL4A5 variant induces aberrant mRNA splicing and transcript deletion. Conclusion We identified a novel intronic COL4A5 pathogenic mutation (c.321+5G>A) in a Chinese XLAS family and described the phenotypes of affected relatives. This study expands the mutation spectrum of COL4A5 gene in XLAS and demonstrates the importance of gene screening for AS.
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Affiliation(s)
- Yang Li
- Department of Nephropathy, Affiliated Haikou Hospital of Xiangya Medical College, Central South University, Hainan, People’s Republic of China
| | - Xue Yan
- Department of Medicine, Shanghai WeHealth Biomedical Technology Co., Ltd., Shanghai, People’s Republic of China
| | - Zhen Luo
- Department of Nephropathy, Affiliated Haikou Hospital of Xiangya Medical College, Central South University, Hainan, People’s Republic of China
| | - Xianxian Fu
- Department of Nephropathy, Affiliated Haikou Hospital of Xiangya Medical College, Central South University, Hainan, People’s Republic of China
| | - Zhongju Li
- Department of Nephropathy, Affiliated Haikou Hospital of Xiangya Medical College, Central South University, Hainan, People’s Republic of China
| | - Qiuzhu Xu
- Department of Central Supply Service Department, Haikou Orthopedic and Diabetes Hospital, Hainan, People’s Republic of China
| | - Juanjuan Chen
- Department of Nephropathy, Affiliated Haikou Hospital of Xiangya Medical College, Central South University, Hainan, People’s Republic of China
| | - Jingmin Yang
- Department of Medicine, Shanghai WeHealth Biomedical Technology Co., Ltd., Shanghai, People’s Republic of China
- NHC Key Laboratory of Birth Defects and Reproductive Health (Chongqing Key Laboratory of Birth Defects and Reproductive Health, Chongqing Population and Family Planning, Science and Technology Research Institute), Chongqing, People’s Republic of China
- State Key Laboratory of Genetic Engineering and MOE Engineering Research Center of Gene Technology, School of Life Sciences, Fudan University, Shanghai, People’s Republic of China
| | - Daru Lu
- NHC Key Laboratory of Birth Defects and Reproductive Health (Chongqing Key Laboratory of Birth Defects and Reproductive Health, Chongqing Population and Family Planning, Science and Technology Research Institute), Chongqing, People’s Republic of China
- State Key Laboratory of Genetic Engineering and MOE Engineering Research Center of Gene Technology, School of Life Sciences, Fudan University, Shanghai, People’s Republic of China
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Lujinschi ȘN, Sorohan BM, Obrișcă B, Vrabie A, Lupușoru G, Achim C, Andronesi AG, Covic A, Ismail G. Genotype-Phenotype Correlations in Alport Syndrome-A Single-Center Experience. Genes (Basel) 2024; 15:593. [PMID: 38790222 PMCID: PMC11121304 DOI: 10.3390/genes15050593] [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: 04/14/2024] [Revised: 05/02/2024] [Accepted: 05/03/2024] [Indexed: 05/26/2024] Open
Abstract
BACKGROUND Alport syndrome (AS) is a common and heterogeneous genetic kidney disease, that often leads to end-stage kidney disease (ESKD). METHODS This is a single-center, retrospective study that included 36 adults with type IV collagen (COL4) mutations. Our main scope was to describe how genetic features influence renal survival. RESULTS A total of 24 different mutations were identified, of which eight had not been previously described. Mutations affecting each of the type IV collagen α chains were equally prevalent (33.3%). Most of the patients had pathogenic variants (61.1%). Most patients had a family history of kidney disease (71%). The most prevalent clinical picture was nephritic syndrome (64%). One-third of the subjects had extrarenal manifestations, 41.6% of patients had ESKD at referral, and another 8.3% developed ESKD during follow-up. The median renal survival was 42 years (95% CI, 29.98-54.01). The COL4A4 group displayed better renal survival than the COL4A3 group (p = 0.027). Patients with missense variants had higher renal survival (p = 0.023). Hearing loss was associated with lower renal survival (p < 0.001). CONCLUSIONS Patients with COL4A4 variants and those with missense mutations had significantly better renal survival, whereas those with COL4A3 variants and those with hearing loss had worse prognoses.
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Affiliation(s)
- Ștefan Nicolaie Lujinschi
- Department of Nephrology, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (B.M.S.); (B.O.); (A.V.); (G.L.); (C.A.); (A.G.A.); (G.I.)
- Department of Nephrology, Fundeni Clinical Institute, 022328 Bucharest, Romania
| | - Bogdan Marian Sorohan
- Department of Nephrology, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (B.M.S.); (B.O.); (A.V.); (G.L.); (C.A.); (A.G.A.); (G.I.)
- Department of Nephrology, Fundeni Clinical Institute, 022328 Bucharest, Romania
| | - Bogdan Obrișcă
- Department of Nephrology, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (B.M.S.); (B.O.); (A.V.); (G.L.); (C.A.); (A.G.A.); (G.I.)
- Department of Nephrology, Fundeni Clinical Institute, 022328 Bucharest, Romania
| | - Alexandra Vrabie
- Department of Nephrology, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (B.M.S.); (B.O.); (A.V.); (G.L.); (C.A.); (A.G.A.); (G.I.)
- Department of Nephrology, Fundeni Clinical Institute, 022328 Bucharest, Romania
| | - Gabriela Lupușoru
- Department of Nephrology, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (B.M.S.); (B.O.); (A.V.); (G.L.); (C.A.); (A.G.A.); (G.I.)
- Department of Nephrology, Fundeni Clinical Institute, 022328 Bucharest, Romania
| | - Camelia Achim
- Department of Nephrology, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (B.M.S.); (B.O.); (A.V.); (G.L.); (C.A.); (A.G.A.); (G.I.)
- Department of Nephrology, Fundeni Clinical Institute, 022328 Bucharest, Romania
| | - Andreea Gabriella Andronesi
- Department of Nephrology, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (B.M.S.); (B.O.); (A.V.); (G.L.); (C.A.); (A.G.A.); (G.I.)
- Department of Nephrology, Fundeni Clinical Institute, 022328 Bucharest, Romania
| | - Andreea Covic
- Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania;
- Nephrology Depatment, Dialysis and Renal Transplant Center, “Dr. C. I. Parhon” Clinical Hospital, 700503 Iasi, Romania
| | - Gener Ismail
- Department of Nephrology, “Carol Davila” University of Medicine and Pharmacy, 020021 Bucharest, Romania; (B.M.S.); (B.O.); (A.V.); (G.L.); (C.A.); (A.G.A.); (G.I.)
- Department of Nephrology, Fundeni Clinical Institute, 022328 Bucharest, Romania
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Chavez E, Goncalves S, Rheault MN, Fornoni A. Alport Syndrome. ADVANCES IN KIDNEY DISEASE AND HEALTH 2024; 31:170-179. [PMID: 39004457 DOI: 10.1053/j.akdh.2024.02.004] [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: 07/19/2023] [Revised: 02/10/2024] [Accepted: 02/28/2024] [Indexed: 07/16/2024]
Abstract
Alport syndrome (AS) is characterized by progressive kidney failure, hematuria, sensorineural hearing loss, and ocular abnormalities. Pathogenic variants in the COL4A3-5 genes result in a defective deposition of the collagen IV α3α4α5 protomers in the basement membranes of the glomerulus in the kidney, the cochlea in the ear and the cornea, lens capsule and retina in the eye. The presence of a large variety of COL4A3-5 gene(s) pathogenetic variants irrespective of the mode of inheritance (X-linked, autosomal recessive, autosomal dominant, or digenic) with and without syndromic features is better defined as the "Alport spectrum disorder", and represents the most common cause of genetic kidney disease and the second most common cause of genetic kidney failure. The clinical course and prognosis of individuals with AS is highly variable. It is influenced by gender, mode of inheritance, affected gene(s), type of genetic mutation, and genetic modifiers. This review article will discuss the epidemiology, classification, pathogenesis, diagnosis, clinical course with genotype-phenotype correlations, and current and upcoming treatment of patients with AS. It will also review current recommendations with respect to when to evaluate for hearing loss or ophthalmologic abnormalities.
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Affiliation(s)
- Efren Chavez
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL.
| | - Stefania Goncalves
- Department of Otolaryngology-Head and Neck Surgery, University of Miami Miller School of Medicine, University of Miami Ear Institute, Miami, FL
| | - Michelle N Rheault
- Department of Pediatrics, University of Minnesota Masonic Children's Hospital, Minneapolis, MN
| | - Alessia Fornoni
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL; Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, FL.
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Chen S, Xu G, Zhao Z, Du J, Shen B, Li C. A novel COL4A5 splicing mutation causes alport syndrome in a Chinese family. BMC Med Genomics 2024; 17:108. [PMID: 38671472 PMCID: PMC11046743 DOI: 10.1186/s12920-024-01878-8] [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: 12/12/2023] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND Alport syndrome (AS) is characterised by haematuria, proteinuria, a gradual decline in kidney function, hearing loss, and eye abnormalities. The disease is caused by mutations in COL4An (n = 3, 4, 5) that encodes 3-5 chains of type IV collagen in the glomerular basement membrane. AS has three genetic models: X-linked, autosomal recessive, and autosomal dominant. The most common type of AS is X-linked AS, which is caused by COL4A5. METHODS We enrolled children with renal insufficiency and a family history of kidney disorders. The proband was identified using whole-exome sequencing. Sanger sequencing was performed to verify the mutation site. Minigene technology was used to analyse the influence of mutant genes on pre-mRNA shearing, and the Iterative Threading ASSEmbly Refinement (I-TASSER) server was used to analyse the protein structure changes. RESULTS The proband, together with her mother and younger brother, displayed microscopic haematuria and proteinuria, Pathological examination revealed mesangial hyperplasia and sclerosis. A novel mutation (NM_000495.5 c.4298-8G > A) in the intron of the COL4A5 gene in the proband was discovered, which was also present in the proband's mother, brother, and grandmother. In vitro minigene expression experiments verified that the c.4298-8G > A mutation caused abnormal splicing, leading to the retention of six base pairs at the end of intron 46. The I-TASSER software predicted that the mutation affected the hydrogen-bonding structure of COL4A5 and the electrostatic potential on the surface of the protein molecules. CONCLUSIONS Based on the patient's clinical history and genetic traits, we conclude that the mutation at the splicing site c.4298-8G > A of the COL4A5 gene is highly probable to be the underlying cause within this particular family. This discovery expands the genetic spectrum and deepens our understanding of the molecular mechanisms underlying AS.
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Affiliation(s)
- Suyun Chen
- Department of Clinical Laboratory, Taizhou Hospital of Zhejiang Province Affiliated to Wenzhou Medical University, Linhai, China
- Key Laboratory of System Medicine and Precision Diagnosis and Treatment of Taizhou, Linhai, China
| | - Guangbiao Xu
- Department of Nephrology, Taizhou Hospital of Zhejiang Province Affiliated to Wenzhou Medical University, Linhai, China
| | - Zhixin Zhao
- Department of Neurosurgery, Taizhou Hospital of Zhejiang Province Affiliated to Wenzhou Medical University, Linhai, China
| | - Juping Du
- Department of Clinical Laboratory, Taizhou Hospital of Zhejiang Province Affiliated to Wenzhou Medical University, Linhai, China
- Key Laboratory of System Medicine and Precision Diagnosis and Treatment of Taizhou, Linhai, China
| | - Bo Shen
- Department of Clinical Laboratory, Taizhou Hospital of Zhejiang Province Affiliated to Wenzhou Medical University, Linhai, China.
- Key Laboratory of System Medicine and Precision Diagnosis and Treatment of Taizhou, Linhai, China.
| | - Chunping Li
- Department of Nephrology, Taizhou Hospital of Zhejiang Province Affiliated to Wenzhou Medical University, Linhai, China.
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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 2024:10.1007/s10157-024-02503-9. [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] [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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Zhang R, Lang Y, Shi X, Zhang Y, Liu X, Pan F, Qiao D, Teng X, Shao L. Three exonic variants in the COL4A5 gene alter RNA splicing in a minigene assay. Mol Genet Genomic Med 2024; 12:e2395. [PMID: 38400605 PMCID: PMC10891438 DOI: 10.1002/mgg3.2395] [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: 09/05/2023] [Revised: 01/22/2024] [Accepted: 01/24/2024] [Indexed: 02/25/2024] Open
Abstract
BACKGROUND X-linked Alport syndrome (XLAS) is an inherited renal disease caused by rare variants of COL4A5 on chromosome Xq22. Many studies have indicated that single nucleotide variants (SNVs) in exons can disrupt normal splicing process of the pre-mRNA by altering various splicing regulatory signals. The male patients with XLAS have a strong genotype-phenotype correlation. Confirming the effect of variants on splicing can help to predict kidney prognosis. This study aimed to investigate whether single nucleotide substitutions, located within three bases at the 5' end of the exons or internal position of the exons in COL4A5 gene, cause aberrant splicing process. METHODS We analyzed 401 SNVs previously presumed missense and nonsense variants in COL4A5 gene by bioinformatics programs and identified candidate variants that may affect the splicing of pre-mRNA via minigene assays. RESULTS Our study indicated three of eight candidate variants induced complete or partial exon skipping. Variants c.2678G>C and c.2918G>A probably disturb classic splice sites leading to corresponding exon skipping. Variant c.3700C>T may disrupt splicing enhancer motifs accompanying with generation of splicing silencer sequences resulting in the skipping of exon 41. CONCLUSION Our study revealed that two missense variants positioned the first nucleotides of the 5' end of COL4A5 exons and one internal exonic nonsense variant caused aberrant splicing. Importantly, this study emphasized the necessity of assessing the effects of SNVs at the mRNA level.
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Affiliation(s)
- Ran Zhang
- Department of Nephrologythe Affiliated Qingdao Municipal Hospital of Qingdao UniversityQingdaoChina
| | - Yanhua Lang
- Department of Materialsthe Affiliated Qingdao Municipal Hospital of Qingdao UniversityQingdaoChina
| | - Xiaomeng Shi
- Department of Nephrologythe Affiliated Qingdao Municipal Hospital of Qingdao UniversityQingdaoChina
| | - Yiyin Zhang
- Department of Nephrologythe Affiliated Qingdao Municipal Hospital of Qingdao UniversityQingdaoChina
| | - Xuyan Liu
- Department of Nephrologythe Affiliated Qingdao Municipal Hospital of Qingdao UniversityQingdaoChina
| | - Fengjiao Pan
- Department of Nephrologythe Affiliated Qingdao Municipal Hospital of Qingdao UniversityQingdaoChina
| | - Dan Qiao
- Department of Nephrologythe Affiliated Qingdao Municipal Hospital of Qingdao UniversityQingdaoChina
| | - Xin Teng
- Department of Ultrasoundthe Affiliated Qingdao Municipal Hospital of Qingdao UniversityQingdaoChina
| | - Leping Shao
- Department of Nephrologythe Affiliated Qingdao Municipal Hospital of Qingdao UniversityQingdaoChina
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Wu J, Cui Y, Liu T, Gu C, Ma X, Yu C, Cai Y, Shu J, Wang W, Cai C. Whole exome sequencing approach for identification of the molecular etiology in pediatric patients with hematuria. Clin Chim Acta 2024; 554:117795. [PMID: 38262496 DOI: 10.1016/j.cca.2024.117795] [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: 10/05/2023] [Revised: 12/25/2023] [Accepted: 01/20/2024] [Indexed: 01/25/2024]
Abstract
BACKGROUND Hematuria is a common condition in clinical practice of pediatric patients. It is related to a wide spectrum of disorders and has high heterogeneity both clinically and genetically, which contributes to challenges of diagnosis and lead many pediatric patients with hematuria not to receive accurate diagnosis and early management. METHODS In this single center study, 42 children with hematuria were included in Tianjin Children's Hospital between 2019 and 2020. We analyzed the clinical information and performed WES (Whole exome sequencing) for all cases. Then the classification of identified variants was performed according to the American College of Medical Genetics and Genomics (ACMG) guidelines for interpreting sequence variants. For the fragment deletion, qPCR was performed to validate and confirm the inherited pattern. RESULTS For the 42 patients, 16 cases had gross hematuria and 26 had microscopic hematuria. Molecular genetic causes were uncovered in 9 (21.4%) children, including 7 with Alport syndrome (AS), one with polycystic nephropathy and one with lipoprotein glomerulopathy. The genetic causes for other patients were not related with hematuria. CONCLUSIONS WES is a rapid and effective way to evaluate patients with hematuria. The analysis of genotype-phenotype correlations of patients with AS indicated that severe variants were associated with early kidney failure. Secondary findings were not rare in Chinese children, thus the clinician should pay more attention to the clinical interpretation of sequencing results and properly interaction with patients and their family.
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Affiliation(s)
- Jinying Wu
- Tianjin Pediatric Research Institute, Tianjin Children's Hospital (Children's Hospital of Tianjin University), Tianjin Key Laboratory of Birth Defects for Prevention and Treatment, Tianjin 300134, China
| | - Yaqiong Cui
- Tianjin Pediatric Research Institute, Tianjin Children's Hospital (Children's Hospital of Tianjin University), Tianjin Key Laboratory of Birth Defects for Prevention and Treatment, Tianjin 300134, China
| | - Tao Liu
- The department of nephrology, Tianjin Children's Hospital (Children's Hospital of Tianjin University), Tianjin 300134, China
| | - Chunyu Gu
- Tianjin Pediatric Research Institute, Tianjin Children's Hospital (Children's Hospital of Tianjin University), Tianjin Key Laboratory of Birth Defects for Prevention and Treatment, Tianjin 300134, China
| | - Ximeng Ma
- Basic Medical College, Tianjin Medical University, Tianjin 30070, China
| | - Changshun Yu
- Tianjin KingMed Center for Clinical Laboratory Co. Ltd., Tianjin 300392, China
| | - Yingzi Cai
- Department of Medicine,Tianjin University, Tianjin 300110, China
| | - Jianbo Shu
- Tianjin Pediatric Research Institute, Tianjin Children's Hospital (Children's Hospital of Tianjin University), Tianjin Key Laboratory of Birth Defects for Prevention and Treatment, Tianjin 300134, China.
| | - Wenhong Wang
- The department of nephrology, Tianjin Children's Hospital (Children's Hospital of Tianjin University), Tianjin 300134, China.
| | - Chunquan Cai
- Tianjin Pediatric Research Institute, Tianjin Children's Hospital (Children's Hospital of Tianjin University), Tianjin Key Laboratory of Birth Defects for Prevention and Treatment, Tianjin 300134, China.
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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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9
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Rheault MN, McLaughlin HM, Mitchell A, Blake LE, Devarajan P, Warady BA, Gibson KL, Lieberman KV. COL4A gene variants are common in children with hematuria and a family history of kidney disease. Pediatr Nephrol 2023; 38:3625-3633. [PMID: 37204491 DOI: 10.1007/s00467-023-05993-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 03/24/2023] [Accepted: 04/15/2023] [Indexed: 05/20/2023]
Abstract
BACKGROUND Inherited kidney diseases are a common cause of chronic kidney disease (CKD) in children. Identification of a monogenic cause of CKD is more common in children than in adults. This study evaluated the diagnostic yield and phenotypic spectrum of children who received genetic testing through the KIDNEYCODE sponsored genetic testing program. METHODS Unrelated children < 18 years of age who received panel testing through the KIDNEYCODE sponsored genetic testing program from September 2019 through August 2021 were included (N = 832). Eligible children met at least one of the following clinician-reported criteria: estimated GFR ≤ 90 ml/min/1.73 m2, hematuria, a family history of kidney disease, or suspected or biopsy confirmed Alport syndrome or focal segmental glomerulosclerosis (FSGS) in the tested individual or family member. RESULTS A positive genetic diagnosis was observed in 234 children (28.1%, 95% CI [25.2-31.4%]) in genes associated with Alport syndrome (N = 213), FSGS (N = 9), or other disorders (N = 12). Among children with a family history of kidney disease, 30.8% had a positive genetic diagnosis. Among those with hematuria and a family history of CKD, the genetic diagnostic rate increased to 40.4%. CONCLUSIONS Children with hematuria and a family history of CKD have a high likelihood of being diagnosed with a monogenic cause of kidney disease, identified through KIDNEYCODE panel testing, particularly COL4A variants. Early genetic diagnosis can be valuable in targeting appropriate therapy and identification of other at-risk family members. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Michelle N Rheault
- Masonic Children's Hospital, University of Minnesota, Minneapolis, MN, USA.
| | | | | | | | - Prasad Devarajan
- Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH, USA
| | - Bradley A Warady
- Children's Mercy Kansas City, University of Missouri-Kansas City, Kansas City, MO, USA
| | | | - Kenneth V Lieberman
- Joseph M. Sanzari Children's Hospital, Hackensack Meridian School of Medicine, Hackensack, NJ, USA
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10
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Zeng M, Di H, Liang J, Liu Z. Effectiveness of renin-angiotensin-aldosterone system blockers in patients with Alport syndrome: a systematic review and meta-analysis. Nephrol Dial Transplant 2023; 38:2485-2493. [PMID: 37218713 DOI: 10.1093/ndt/gfad105] [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: 01/04/2023] [Indexed: 05/24/2023] Open
Abstract
BACKGROUND Although renin-angiotensin-aldosterone system (RAAS) blockers have been considered the primary treatment for patients with Alport syndrome (AS) for a decade, there is no comprehensive review with evidence-based analysis evaluating the effectiveness of RAAS blockers in AS. METHODS A systematic review and meta-analysis was performed of published studies that compared outcomes related to disease progression between patients with AS receiving RAAS blockers with those taking non-RAAS treatment. Outcomes were meta-analyzed using the random effects models. Cochrane risk-of-bias, Newcastle-Ottawa Scale and Grading of Recommendations Assessment, Development and Evaluation methodology (GRADE) assessment determined the certainty of evidence. RESULTS A total of eight studies (1182 patients) were included in the analysis. Overall, the risk of bias was low to moderate. Compared with non-RAAS treatment, RAAS blockers could reduce the rate of progression to end-stage kidney disease (ESKD) [four studies; hazard ratio (HR) 0.33, 95% confidence interval (CI) 0.24-0.45; moderate certainty evidence]. After stratified by genetic types, a similar benefit was detected: male X-linked AS (XLAS) (HR 0.32, 95% CI 0.22-0.48), autosomal recessive AS (HR 0.25, 95% CI 0.10-0.62), female XLAS and autosomal dominant AS (HR 0.40, 95% CI 0.21-0.75). In addition, RAAS blockers showed a clear gradient of benefit depending on the stage of disease at the initiation of treatment. CONCLUSION This meta-analysis suggested that RAAS blockers could be considered as a specific therapy to delay of ESKD for AS with any genetic type, especially at the early stage of the disease, and every further more-effective therapy would be advised to be applied on top of this standard of care.
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Affiliation(s)
- Mengyao Zeng
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Hongling Di
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Ju Liang
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
| | - Zhihong Liu
- National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing University School of Medicine, Nanjing, China
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11
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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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12
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Nozu K, Resontoc LPR, Hooman N, Vasudevan A, Ding J, Kang HG. Investigation of the current situation regarding diagnosis and treatment of Alport syndrome in Asian countries: results of survey of the Asian Paediatric Nephrology association (AsPNA) tubular and inherited working group. Clin Exp Nephrol 2023; 27:776-780. [PMID: 37289334 PMCID: PMC10432360 DOI: 10.1007/s10157-023-02358-6] [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: 02/18/2023] [Accepted: 05/02/2023] [Indexed: 06/09/2023]
Abstract
BACKGROUND Alport syndrome is one of the most common inherited kidney diseases worldwide. A genetic test or kidney biopsy is necessary for a definite diagnosis of this disease, and an accurate diagnosis system for this disease is highly desired in each country. However, the current situation in Asian countries is not clear. Therefore, the tubular and inherited disease working group of the Asian Pediatric Nephrology Association (AsPNA) aimed to assess the current situation of diagnosis and treatment for Alport syndrome in Asia. METHODS The group conducted an online survey among the members of AsPNA in 2021-2022. Collected data included the number of patients for each inheritance mode, availability of gene tests or kidney biopsy, and treatment strategies for Alport syndrome. RESULTS A total of 165 pediatric nephrologists from 22 countries in Asia participated. Gene test was available in 129 institutes (78%), but the cost was still expensive in most countries. Kidney biopsy was available in 87 institutes (53%); however, only 70 can access electron microscopy, and 42 can conduct type IV collagen α5 chain staining. Regarding treatment, 140 centers use renin-angiotensin system (RAS) inhibitors (85%) for Alport syndrome patients. CONCLUSIONS This study result might suggest that the system is underdeveloped enough to diagnose all Alport syndrome patients in most Asian countries. However, once diagnosed with Alport syndrome, most of them were treated with RAS inhibitors. These survey results can be used to address knowledge, diagnostic system, and treatment strategy gaps and improve the Alport patients' outcomes in Asian countries.
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Affiliation(s)
- Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo, Kobe, Hyogo, 650-0017, Japan.
| | - Lourdes Paula Real Resontoc
- Division of Pediatric Nephrology, College of Medicine, University of the Philippines-Philippine General Hospital, Manila, Philippines
| | - Nakysa Hooman
- Ali Asghar Clinical Research Development Center, Department of Pediatrics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Anil Vasudevan
- Department of Pediatric Nephrology, St John's Medical College Hospital, Bengaluru, India
| | - Jie Ding
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Hee Gyung Kang
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, South Korea
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13
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Deltas C, Papagregoriou G, Louka SF, Malatras A, Flinter F, Gale DP, Gear S, Gross O, Hoefele J, Lennon R, Miner JH, Renieri A, Savige J, Turner AN. Genetic Modifiers of Mendelian Monogenic Collagen IV Nephropathies in Humans and Mice. Genes (Basel) 2023; 14:1686. [PMID: 37761826 PMCID: PMC10530214 DOI: 10.3390/genes14091686] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/09/2023] [Accepted: 08/17/2023] [Indexed: 09/29/2023] Open
Abstract
Familial hematuria is a clinical sign of a genetically heterogeneous group of conditions, accompanied by broad inter- and intrafamilial variable expressivity. The most frequent condition is caused by pathogenic (or likely pathogenic) variants in the collagen-IV genes, COL4A3/A4/A5. Pathogenic variants in COL4A5 are responsible for the severe X-linked glomerulopathy, Alport syndrome (AS), while homozygous or compound heterozygous variants in the COL4A3 or the COL4A4 gene cause autosomal recessive AS. AS usually leads to progressive kidney failure before the age of 40-years when left untreated. People who inherit heterozygous COL4A3/A4 variants are at-risk of a slowly progressive form of the disease, starting with microscopic hematuria in early childhood, developing Alport spectrum nephropathy. Sometimes, they are diagnosed with benign familial hematuria, and sometimes with autosomal dominant AS. At diagnosis, they often show thin basement membrane nephropathy, reflecting the uniform thin glomerular basement membrane lesion, inherited as an autosomal dominant condition. On a long follow-up, most patients will retain normal or mildly affected kidney function, while a substantial proportion will develop chronic kidney disease (CKD), even kidney failure at an average age of 55-years. A question that remains unanswered is how to distinguish those patients with AS or with heterozygous COL4A3/A4 variants who will manifest a more aggressive kidney function decline, requiring prompt medical intervention. The hypothesis that a subgroup of patients coinherit additional genetic modifiers that exacerbate their clinical course has been investigated by several researchers. Here, we review all publications that describe the potential role of candidate genetic modifiers in patients and include a summary of studies in AS mouse models.
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Affiliation(s)
- Constantinos Deltas
- School of Medicine, University of Cyprus, Nicosia 2109, Cyprus
- biobank.cy Center of Excellence in Biobanking and Biomedical Research, University of Cyprus, Nicosia 2109, Cyprus
| | - Gregory Papagregoriou
- biobank.cy Center of Excellence in Biobanking and Biomedical Research, University of Cyprus, Nicosia 2109, Cyprus
| | - Stavroula F. Louka
- biobank.cy Center of Excellence in Biobanking and Biomedical Research, University of Cyprus, Nicosia 2109, Cyprus
| | - Apostolos Malatras
- biobank.cy Center of Excellence in Biobanking and Biomedical Research, University of Cyprus, Nicosia 2109, Cyprus
| | - Frances Flinter
- Clinical Genetics Department, Guy’s & St Thomas’ NHS Foundation Trust, London SE1 9RT, UK
| | - Daniel P. Gale
- Department of Renal Medicine, University College London, London NW3 2PF, UK
| | | | - Oliver Gross
- Clinic for Nephrology and Rheumatology, University Medicine Goettingen, 37075 Goettingen, Germany
| | - Julia Hoefele
- Institute of Human Genetics, Klinikum Rechts der Isar, School of Medicine & Health, Technical University Munich, 81675 Munich, Germany
| | - Rachel Lennon
- Wellcome Centre for Cell-Matrix Research, University of Manchester, Manchester M13 9WU, UK
| | - Jeffrey H. Miner
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Alessandra Renieri
- Medical Genetics, University of Siena, 53100 Siena, Italy
- Med Biotech Hub and Competence Center, Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy
- Genetica Medica, Azienda Ospedaliero-Universitaria Senese, 53100 Siena, Italy
| | - Judy Savige
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Parkville, VIC 3052, Australia
| | - A. Neil Turner
- Renal Medicine, Royal Infirmary, University of Edinburgh, Edinburgh EH16 4UX, UK
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14
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Liu N, Wen X, Ou Z, Fang X, Du J, Lin X. Case report: Preimplantation genetic testing for X-linked alport syndrome caused by variation in the COL4A5 gene. Front Pediatr 2023; 11:1177019. [PMID: 37635800 PMCID: PMC10448762 DOI: 10.3389/fped.2023.1177019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 07/28/2023] [Indexed: 08/29/2023] Open
Abstract
X-Linked Alport Syndrome (XLAS) is an X-linked, dominant, hereditary nephropathy mainly caused by mutations in the COL4A5 gene, found on chromosome Xq22. In this study, we reported a pedigree with XLAS caused by a COL4A5 mutation. This family gave birth to a boy with XLAS who developed hematuria and proteinuria at the age of 1 year. We used next-generation sequencing (NGS) to identify mutations in the proband and his parents and confirmed the results using Sanger sequencing. This testing showed there was a single nucleotide missense variation, c.3659G>A (p.Gly1220Asp) (NM_033380.3), in the COL4A5 gene. To prevent the inheritance of the syndrome, we used eight embryos for trophoblast biopsy after assisted reproductive technology treatment, and whole genome amplification (WGA) was performed using multiple annealing and looping-based amplification cycles (MALBAC). Embryos were subjected to Preimplantation Genetic Testing (PGT) procedures, including Sanger sequencing, NGS-based single nucleotide polymorphism (SNP) haplotype linkage analysis, and chromosomal copy number variation (CNV) analysis. The results showed that three embryos (E1, E2, and E4) were free of CNV and genetic variation in the COL4A5 gene. Embryo E1 (4AA) was transferred after consideration of the embryo growth rate, morphology, and PGT results. Prenatal diagnosis in the second trimester showed that the fetus had a normal karyotype and did not carry the COL4A5 mutation (c.3659G>A). Ultimately, a healthy boy was born and did not carry the pathogenic COL4A5 mutation, which indicated that PGT prevented the intergenerational transmission of the causative mutation of XLAS.
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Affiliation(s)
- Nengqing Liu
- Reproductive Center, Zhongshan Boai Hospital, Zhongshan, China
| | - Xiaojun Wen
- Reproductive Center, Zhongshan Boai Hospital, Zhongshan, China
| | - Zhanhui Ou
- Reproductive Center, Zhongshan Boai Hospital, Zhongshan, China
| | - Xiaowu Fang
- Reproductive Center, Zhongshan Boai Hospital, Zhongshan, China
| | - Jing Du
- Reproductive Center, Zhongshan Boai Hospital, Zhongshan, China
| | - Xiufeng Lin
- Reproductive Center, Zhongshan Boai Hospital, Zhongshan, China
- The Second Clinical College, Southern Medical University, Guangzhou, China
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15
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Shanks J, Butler G, Cheng D, Jayasinghe K, Quinlan C. Clinical and diagnostic utility of genomic sequencing for children referred to a Kidney Genomics Clinic with microscopic haematuria. Pediatr Nephrol 2023; 38:2623-2630. [PMID: 36715773 DOI: 10.1007/s00467-022-05846-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 11/17/2022] [Accepted: 12/05/2022] [Indexed: 01/31/2023]
Abstract
BACKGROUND Microscopic haematuria in children is associated with the risk of progression to chronic kidney disease. Genetic disease is an important potential aetiology. Genomic sequencing presents the most effective diagnostic route for these conditions, but access remains inequitable internationally. METHODS We conducted a retrospective review of the electronic medical records of a Kidney Genomics Clinic (KGC) from January 2016 to December 2021. RESULTS Sixty patients were referred to the KGC with haematuria over this period. Forty-three percent of patients had analysis of a limited haematuria panel (COL4A1, COL4A3, COL4A4, COL4A5, MYH9) with 58% receiving a genetic diagnosis. Forty-two percent of referred patients had further analysis of genes implicated in the development of kidney disease, and 36% received a diagnosis. Eight percent of patients underwent cascade testing for a known familial variant, and all received a diagnosis. Children with the highest levels of haematuria (> 500 × 106/L red blood cells) had the highest diagnostic yield (67%). Proteinuria, defined as a urinary protein to creatinine ratio > 20, increased the diagnostic yield from 31 to 65%. Importantly, negative genetic analysis can still have significant clinical utility for patients by altering surveillance and further management; the genetic result had clinical utility in 60% of patients. CONCLUSIONS Our KGC review highlights the substantial clinical utility and diagnostic yield of genomic analysis for microscopic haematuria in paediatric patients. Whilst the management of variants of uncertain significance can be challenging, a multidisciplinary team including genetic counselling can help ensure these patients are followed up meaningfully. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Josiah Shanks
- Department of Nephrology, Royal Children's Hospital, Melbourne, Australia.
- Digital Health, Melbourne Children's Centre for Health Analytics, Melbourne, Australia.
- Kidney Flagship, Murdoch Children's Research Institute, Melbourne, Australia.
| | - Grainne Butler
- Department of Nephrology, Royal Children's Hospital, Melbourne, Australia
- Digital Health, Melbourne Children's Centre for Health Analytics, Melbourne, Australia
- Kidney Flagship, Murdoch Children's Research Institute, Melbourne, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Daryl Cheng
- Digital Health, Melbourne Children's Centre for Health Analytics, Melbourne, Australia
| | - Kushani Jayasinghe
- Kidney Flagship, Murdoch Children's Research Institute, Melbourne, Australia
| | - Catherine Quinlan
- Department of Nephrology, Royal Children's Hospital, Melbourne, Australia
- Digital Health, Melbourne Children's Centre for Health Analytics, Melbourne, Australia
- Kidney Flagship, Murdoch Children's Research Institute, Melbourne, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Australia
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16
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Pan S, Yu R, Liang S. Case report: A case report of Alport syndrome caused by a novel mutation of COL4A5. Front Genet 2023; 14:1216809. [PMID: 37529776 PMCID: PMC10389043 DOI: 10.3389/fgene.2023.1216809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 06/30/2023] [Indexed: 08/03/2023] Open
Abstract
Alport syndrome (#308940) is an X-linked genetic disease with clinical manifestations, such as hematuria, proteinuria, renal insufficiency, and end-stage renal disease. The disease is characterized by the thinning of the glomerular basement membrane in the early stages and the thickening of the glomerular basement membrane in the late stages and may be associated with ocular lesions and varying degrees of sensorineural deafness. Herein, we report a case of Alport syndrome caused by a de novo mutation in COL4A5. The patient was a young male with clinical manifestations of hematuria and massive proteinuria who was diagnosed with Alport syndrome based on renal pathology and genetic testing.
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Affiliation(s)
- Shujun Pan
- Clinical School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Rizhen Yu
- Urology & Nephrology Center, Department of Nephrology, Zhejiang Provincial People’s Hospital, Affiliated People’s Hospital, Hangzhou Medical College, Hangzhou, Zhejiang, China
| | - Shikai Liang
- Urology & Nephrology Center, Department of Nephrology, Zhejiang Provincial People’s Hospital, Affiliated People’s Hospital, Hangzhou Medical College, Hangzhou, Zhejiang, China
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17
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Zhang Y, Wang X, Zhou J, Ding J, Wang F. Abnormal mRNA Splicing Effect of COL4A3 to COL4A5 Unclassified Variants. Kidney Int Rep 2023; 8:1399-1406. [PMID: 37441478 PMCID: PMC10334324 DOI: 10.1016/j.ekir.2023.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/30/2023] [Accepted: 04/03/2023] [Indexed: 07/15/2023] Open
Abstract
Introduction Genetic diagnosis of Alport syndrome (AS), which results from pathogenic variants in COL4A3, COL4A4, or COL4A5 genes, is hindered by large numbers of unclassified variants detected using next-generation sequencing (NGS). We examined the impact on splicing of variants of uncertain significance in COL4A3 to COL4A5. Methods Nine unrelated patients with clinical diagnosis or suspicion of AS were enrolled according to the criteria. Their clinical and genetic data were collected. Blood and urine samples were obtained from the patients and their family members. Sanger sequencing was used to confirm the 9 COL4A3 to COL4A5 unclassified variants identified by NGS. COL4A3 to COL4A5 mRNAs from urine were analyzed using targeted reverse transcription polymerase chain reaction and direct sequencing. Results Nine COL4A3 to COL4A5 unclassified variants were found to alter mRNAs splicing. Skipping of an exon or an exon fragment was induced by variants COL4A3 c.828+5G>A; COL4A4 c.3506-13_3528del; and COL4A5 c.451A>G (p. [Ile151Val]), c.2042-9 T>G, c.2689 G>C (p. [Glu897Gln]) and c.1033-10_1033-2delGGTAATAAA. Retention of an intron fragment was caused by variants COL4A3 c.3211-30G>T, and COL4A5 c.4316-20T>A and c.1033-10 G>A, respectively. The 9 families in this study obtained genetic diagnosis of AS, including 3 with autosomal recessive AS and 6 with X-linked AS. Conclusions Our findings demonstrate that urine mRNA analysis facilitates the identification of abnormal splicing of unclassified variants in Alport genes, which provides evidence of routine use of RNA analysis to improve genetic diagnosis of AS.
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Affiliation(s)
- Yanqin Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xiaoyuan Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jianmei Zhou
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jie Ding
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Fang Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
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18
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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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19
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Zhang H, Wang F, Xiao H. Combined Alport syndrome, Klinefelter syndrome and Fanconi syndrome in a Chinese boy. Nephrology (Carlton) 2023; 28:272-275. [PMID: 36878861 DOI: 10.1111/nep.14152] [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: 12/08/2022] [Revised: 02/19/2023] [Accepted: 02/20/2023] [Indexed: 03/08/2023]
Abstract
Alport syndrome (AS) is a progressive renal disease characterized by hematuria and progressive renal failure. X-linked dominant (XLAS) is the major inheritance form, accounting for almost 80% of the cases, caused by mutations in COL4A5 genes. Klinefelter syndrome (KS) is the most common genetic cause of human male gonadal dysgenesis. AS and KS are both rare disease, there are only three cases of combined AS and KS in the literatures. Fanconi syndrome (FS) caused by AS is also very rare. We report here the first case combined AS, KS and FS in a Chinese boy. We suggest that the severe renal phenotype and FS might be due to the two homozygous COL4A5 variants in our boy, and cases of AS combined KS will be good research objects for X chromosome inactivation.
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Affiliation(s)
- Hongwen Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, People's Republic of China
| | - Fang Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, People's Republic of China
| | - Huijie Xiao
- Department of Pediatrics, Peking University First Hospital, Beijing, People's Republic of China
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20
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Alge JL, Bekheirnia N, Willcockson AR, Qin X, Scherer SE, Braun MC, Bekheirnia MR. Variants in genes coding for collagen type IV α-chains are frequent causes of persistent, isolated hematuria during childhood. Pediatr Nephrol 2023; 38:687-695. [PMID: 35759000 DOI: 10.1007/s00467-022-05627-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 05/04/2022] [Accepted: 05/06/2022] [Indexed: 01/19/2023]
Abstract
BACKGROUND Children with persistent, isolated microscopic hematuria typically undergo a limited diagnostic workup and are monitored for signs of kidney disease in long-term longitudinal follow-up, which can delay diagnosis and allow disease progression in some cases. METHODS To determine the clinical utility of genetic screening in this population, we performed targeted genetic testing using a custom, 32-gene next-generation sequencing panel for progressive kidney disease on children referred to the Texas Children's Hospital Pediatric Nephrology clinic for persistent, microscopic hematuria (n = 30; cohort 1). Patients with microscopic hematuria identified by urinalysis on at least two separate occasions were eligible for enrollment, but those with other evidence of kidney disease were excluded. Results were analyzed for sequence variants using the American College of Medical Genetics and Genomics (ACMG) guideline for data interpretation and were validated using a secondary analysis of a dataset of children with hematuria and normal kidney function who had undergone genetic testing as part of an industry-sponsored program (cohort 2; n = 67). RESULTS In cohort 1 33% of subjects (10/30) had pathogenic or likely pathogenic (P/LP) variants in the type IV collagen genes (COL4A3/A4/A5), and 10% (3/30) had variants of uncertain significance in these genes. The high diagnostic rate in type IV collagen genes was confirmed in cohort 2, where 27% (18/67) of subjects had P/LP variants in COL4A3/A4/A5 genes. CONCLUSIONS Children with persistent, isolated microscopic hematuria have a high likelihood of having pathogenic variants in type IV collagen genes and genetic screening should be considered. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Joseph L Alge
- Department of Pediatrics, Division of Pediatric Nephrology, Baylor College Medicine, Houston, TX, 77030, USA
| | - Nasim Bekheirnia
- Department of Pediatrics, Division of Pediatric Nephrology, Baylor College Medicine, Houston, TX, 77030, USA
| | | | - Xiang Qin
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Steven E Scherer
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Michael C Braun
- Department of Pediatrics, Division of Pediatric Nephrology, Baylor College Medicine, Houston, TX, 77030, USA
| | - Mir Reza Bekheirnia
- Department of Pediatrics, Division of Pediatric Nephrology, Baylor College Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.
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21
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Watanabe H, Goto S, Hosojima M, Kabasawa H, Imai N, Ito Y, Narita I. Pathogenic variants of Alport syndrome and monogenic diabetes identified by exome sequencing in a family. Hum Genome Var 2023; 10:5. [PMID: 36732323 PMCID: PMC9894847 DOI: 10.1038/s41439-023-00233-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/30/2022] [Accepted: 01/03/2023] [Indexed: 02/04/2023] Open
Abstract
We present a family of two female Alport syndrome patients with a family history of impaired glucose tolerance. Whole exome sequencing identified a novel heterozygous variant of COL4A5 NM_033380.3: c.2636 C > A (p.S879*) and a rare variant of GCK NM_001354800.1: c.1135 G > A (p.A379T) as the causes of Alport syndrome and monogenic diabetes, respectively. Two independent pathogenic variants affected the clinical phenotypes. Clinical next-generation sequencing is helpful for identifying the causes of patients' manifestations.
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Affiliation(s)
- Hirofumi Watanabe
- Division of Clinical Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
| | - Shin Goto
- Division of Clinical Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Michihiro Hosojima
- Department of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hideyuki Kabasawa
- Department of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Naofumi Imai
- Division of Clinical Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yumi Ito
- Division of Clinical Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
- Department of Health Promotion Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Ichiei Narita
- Division of Clinical Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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22
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Abstract
Hundreds of different genetic causes of chronic kidney disease are now recognized, and while individually rare, taken together they are significant contributors to both adult and pediatric diseases. Traditional genetics approaches relied heavily on the identification of large families with multiple affected members and have been fundamental to the identification of genetic kidney diseases. With the increased utilization of massively parallel sequencing and improvements to genotype imputation, we can analyze rare variants in large cohorts of unrelated individuals, leading to personalized care for patients and significant research advancements. This review evaluates the contribution of rare disorders to patient care and the study of genetic kidney diseases and highlights key advancements that utilize new techniques to improve our ability to identify new gene-disease associations.
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Affiliation(s)
- Mark D Elliott
- Division of Nephrology, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA;
- Center for Precision Medicine and Genomics, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Institute for Genomic Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Hila Milo Rasouly
- Division of Nephrology, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA;
- Center for Precision Medicine and Genomics, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Ali G Gharavi
- Division of Nephrology, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA;
- Center for Precision Medicine and Genomics, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Institute for Genomic Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
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23
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Aberrant splicing caused by exonic single nucleotide variants positioned 2nd or 3rd to the last nucleotide in the COL4A5 gene. Clin Exp Nephrol 2023; 27:218-226. [PMID: 36371577 PMCID: PMC9950164 DOI: 10.1007/s10157-022-02294-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 10/27/2022] [Indexed: 11/13/2022]
Abstract
BACKGROUND AND OBJECTIVES The evident genotype-phenotype correlation shown by the X-linked Alport syndrome warrants the assessment of the impact of identified gene variants on aberrant splicing. We previously reported that single nucleotide variants (SNVs) in the last nucleotide of exons in COL4A5 cause aberrant splicing. It is known that the nucleotides located 2nd and 3rd to the last nucleotides of exons can also play an essential role in the first step of the splicing process. In this study, we aimed to investigate whether SNVs positioned 2nd or 3rd to the last nucleotide of exons in COL4A5 resulted in aberrant splicing. METHODS We selected eight candidate variants: six from the Human Gene Variant Database Professional and two from our cohort. We performed an in-vitro splicing assay and reverse transcription-polymerase chain reaction (RT-PCR) for messenger RNA obtained from patients, if available. RESULTS The candidate variants were initially classified into the following groups: three nonsense, two missense, and three synonymous variants. Splicing assays and RT-PCR for messenger RNA revealed that six of the eight variants caused aberrant splicing. Four variants, initially classified as non-truncating variants, were found to be truncating ones, which usually show relatively more severe phenotypes. CONCLUSION We revealed that exonic SNVs positioned 2nd or 3rd to the last nucleotide of exons in the COL4A5 were responsible for aberrant splicing. The results of our study suggest that attention should be paid when interpreting the pathogenicity of exonic SNVs near the 5' splice site.
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24
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Di H, Zhang J, Gao E, Zheng C, Huang X, Wang Q, Yu X, Liu Z. Dissecting the genotype-phenotype correlation of COL4A5 gene mutation and its response to renin-angiotensin-aldosterone system blockers in Chinese male patients with Alport syndrome. Nephrol Dial Transplant 2022; 37:2487-2495. [PMID: 35020912 DOI: 10.1093/ndt/gfac002] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Alport syndrome (AS) is an inherited type IV collagen-related disorder with an irreversible tendency to progress to end-stage renal disease (ESRD). X-linked AS (XLAS) is caused by mutations in the COL4A5 gene. The aim of this study was to investigate the effects of underlying mutations on clinical manifestations and the response to therapy in XLAS. METHODS We conducted a retrospective cohort study of 187 Chinese male patients with XLAS confirmed by pathological examination and genetic analysis. The Kaplan-Meier method and Cox proportional hazards model were used to assess the age and risk of progression to ESRD under different genotypes and treatment conditions. RESULTS A strong relationship between transcript type and renal outcome was observed, with the median age of ESRD onset being 22 years for truncating mutations and 39 years for non-truncating mutations. The response of affected patients to renin-angiotensin-aldosterone system (RAAS) blockers was genotype-associated. This therapy delayed the onset of ESRD by 16 years in patients with non-truncating mutations and 3 years in patients with truncating mutations. The efficacy of RAAS blockers functioned in a time-dependent manner, with a 7% reduction in the risk of progression to ESRD per each 6-month increase in treatment duration [hazard ratio 0.93 (95% confidence interval 0.89-0.96); P < 0.001]. CONCLUSIONS Clinical features and response to RAAS blockers were observed to be strongly correlated with the genotypes of male XLAS patients. Genotyping of COL4A5 gene mutations is essential and is a useful tool to assess the prognosis of AS patients.
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Affiliation(s)
- Hongling Di
- National Clinical Research Center of Kidney Diseases, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Jiahui Zhang
- Key Laboratory of Biosystems Homeostasis and Protection of the 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, China
| | - Chunxia Zheng
- National Clinical Research Center of Kidney Diseases, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Xianghua Huang
- National Clinical Research Center of Kidney Diseases, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, China
| | - Qing Wang
- National Clinical Research Center of Kidney Diseases, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing, 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, China
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25
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Boeckhaus J, Hoefele J, Riedhammer KM, Nagel M, Beck BB, Choi M, Gollasch M, Bergmann C, Sonntag JE, Troesch V, Stock J, Gross O. Lifelong effect of therapy in young patients with the COL4A5 Alport missense variant p.(Gly624Asp): a prospective cohort study. Nephrol Dial Transplant 2022; 37:2496-2504. [PMID: 35022790 DOI: 10.1093/ndt/gfac006] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Angiotensin-converting enzyme inhibitors (ACEis) have evolved as a first-line therapy for delaying end-stage renal failure (ESRF) in Alport syndrome (AS). The present study tested the hypothesis of a superior nephroprotective potential of an early ACEi intervention, examining a cohort with the COL4A5 missense variant p.(Gly624Asp). METHODS In this observational cohort study (NCT02378805), 114 individuals with the identical gene variant were explored for age at ESRF and life expectancy in correlation with treatment as endpoints. RESULTS All 13 untreated hemizygous patients developed ESRF (mean age 48.9 ± 13.7 years), as did 3 very late treated hemizygotes (51.7 ± 4.2 years), with a mean life expectancy of 59.2 ± 9.6 years. All 28 earlier-treated [estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2] hemizygous patients were still alive and still had not reached ESRF. Therapy minimized the annual loss of their GFR, similar to the annual loss in healthy individuals. Of 65 heterozygotes, 4 untreated individuals developed ESRF at an age of 53.3 ± 20.7 years. None of the treated heterozygous females developed ESRF. CONCLUSIONS For the first time, this study shows that in AS, early therapy in individuals with missense variants might have the potential to delay renal failure for their lifetime and thus to improve life expectancy and quality of life without the need for renal replacement therapy. Some treated patients have reached their retirement age with still-functioning kidneys, whereas their untreated relatives have reached ESRF at the same or a younger age. Thus, in children with glomerular haematuria, early testing for Alport-related gene variants could lead to timely nephroprotective intervention.
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Affiliation(s)
- Jan Boeckhaus
- Clinic for Nephrology and Rheumatology, University Medical Center Göttingen, Göttingen, Germany
| | - Julia Hoefele
- Institute of Human Genetics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Korbinian M Riedhammer
- Institute of Human Genetics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.,Department of Nephrology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Mato Nagel
- Center for Nephrology and Metabolic Medicine, Weisswasser, Germany
| | - Bodo B Beck
- Institute of Human Genetics, Center for Molecular Medicine Cologne, and Center for Rare and Hereditary Kidney Disease, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Mira Choi
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Maik Gollasch
- Department of Internal and Geriatric Medicine, University Medicine Greifswald, Greifswald, Germany.,Experimental and Clinical Research Center, Charité University Medicine Berlin, Berlin, Germany
| | - Carsten Bergmann
- Department of Medicine, Nephrology, University Hospital Freiburg, Germany.,Medizinische Genetik Mainz, Limbach Genetics, Mainz, Germany
| | - Joseph E Sonntag
- Clinic for Nephrology and Rheumatology, University Medical Center Göttingen, Göttingen, Germany
| | - Victoria Troesch
- Clinic for Nephrology and Rheumatology, University Medical Center Göttingen, Göttingen, Germany
| | - Johanna Stock
- Clinic for Nephrology and Rheumatology, University Medical Center Göttingen, Göttingen, Germany
| | - Oliver Gross
- Clinic for Nephrology and Rheumatology, University Medical Center Göttingen, Göttingen, Germany
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26
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Savige J, Renieri A, Ars E, Daga S, Pinto AM, Rothe H, Gale DP, Aksenova M, Cerkauskaite A, Bielska O, Lipska-Zietkiewicz B, Gibson JT. Digenic Alport Syndrome. Clin J Am Soc Nephrol 2022; 17:1697-1706. [PMID: 35675912 PMCID: PMC9718039 DOI: 10.2215/cjn.03120322] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Digenic Alport syndrome refers to the inheritance of pathogenic variants in COL4A5 plus COL4A3 or COL4A4 or in COL4A3 plus COL4A4 Where digenic Alport syndrome includes a pathogenic COL4A5 variant, the consequences depend on the sex of the affected individual, COL4A5 variant "severity," and the nature of the COL4A3 or COL4A4 change. A man with a pathogenic COL4A5 variant has all his collagen IV α3α4α5-heterotrimers affected, and an additional COL4A3 or COL4A4 variant may not worsen disease. A woman with a pathogenic COL4A5 variant has on average 50% of her heterotrimers affected, which is increased to 75% with a further COL4A3 or COL4A4 variant and associated with a higher risk of proteinuria. In digenic Alport syndrome with pathogenic COL4A3 and COL4A4 variants, 75% of the heterotrimers are affected. The COL4A3 and COL4A4 genes occur head-to-head on chromosome 2, and inheritance is autosomal dominant when both variants affect the same chromosome (in cis) or recessive when they affect different chromosomes (in trans). This form of digenic disease results in increased proteinuria and a median age of kidney failure intermediate between autosomal dominant and autosomal recessive Alport syndrome. Previous guidelines have suggested that all pathogenic or likely pathogenic digenic variants should be identified and reported. Affected family members should be identified, treated, and discouraged from kidney donation. Inheritance within a family is easier to predict if the two variants are considered independently and if COL4A3 and COL4A4 variants are known to be inherited on the same or different chromosomes.
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Affiliation(s)
- Judy Savige
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Parkville, Victoria, Australia
| | - Alessandra Renieri
- Medical Genetics Unit, University of Siena, Siena, Italy
- Med Biotech Hub and Competence Center, Department of Medical Biotechnologies, University of Siena, Siena, Italy
- Genetics Medica, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Elisabet Ars
- Department of Nephrology, Molecular Biology Laboratory , Fundacio Puigvert, Instituto de Investigaciones Biomédicas Sant Pau, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Sergio Daga
- Medical Genetics Unit, University of Siena, Siena, Italy
- Med Biotech Hub and Competence Center, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Anna Maria Pinto
- Genetics Medica, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Hansjorg Rothe
- Centre for Nephrology and Metabolic Disorders, Weisswasser, Germany
| | - Daniel P. Gale
- Department of Renal Medicine, University College London, London, United Kingdom
| | - Marina Aksenova
- Department of Nephrology, Veltischev Research and Clinical Institute for Pediatrics of the Pirogov Russian National Research Medical University, Moscow, Russia
| | - Agne Cerkauskaite
- Division of Diagnostics and Treatment of Rare Kidney and Metabolic Diseases, Institute of Biomedical Sciences, Vilnius University, Vilnius, Lithuania
| | - Olga Bielska
- Centre for Rare Diseases and Clinical Genetics Unit, Medical University of Gdansk, Gdansk, Poland
| | - Beata Lipska-Zietkiewicz
- Centre for Rare Diseases and Clinical Genetics Unit, Medical University of Gdansk, Gdansk, Poland
| | - Joel T. Gibson
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Parkville, Victoria, Australia
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27
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An Update on Women and Girls with Alport Syndrome. CURRENT PEDIATRICS REPORTS 2022. [DOI: 10.1007/s40124-022-00279-8] [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: 11/26/2022]
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28
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Kashtan CE. Genetic testing and glomerular hematuria-A nephrologist's perspective. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2022; 190:399-403. [PMID: 35775584 PMCID: PMC9796064 DOI: 10.1002/ajmg.c.31987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 05/25/2022] [Accepted: 06/19/2022] [Indexed: 01/29/2023]
Abstract
Alport syndrome is an inherited disorder of the kidneys that results from variants in three collagen IV genes-COL4A3, COL4A4, and COL4A5. Early diagnosis and pharmacologic intervention can delay the progression of chronic kidney disease and the onset of kidney failure in patients with Alport syndrome. This article describes the evolution of approaches to the diagnosis and early treatment of Alport syndrome.
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Affiliation(s)
- Clifford E. Kashtan
- Division of Pediatric NephrologyUniversity of Minnesota Medical SchoolMinneapolisMinnesotaUSA
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29
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Chavez E, Rodriguez J, Drexler Y, Fornoni A. Novel Therapies for Alport Syndrome. Front Med (Lausanne) 2022; 9:848389. [PMID: 35547199 PMCID: PMC9081811 DOI: 10.3389/fmed.2022.848389] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 03/14/2022] [Indexed: 12/14/2022] Open
Abstract
Alport syndrome (AS) is a hereditary kidney disease associated with proteinuria, hematuria and progressive kidney failure. It is characterized by a defective glomerular basement membrane caused by mutations in type IV collagen genes COL4A3/A4/A5 which result in defective type IV collagen α3, α4, or α5 chains, respectively. Alport syndrome has three different patterns of inheritance: X-linked, autosomal and digenic. In a study of CKD of unknown etiology type IV collagen gene mutations accounted for the majority of the cases of hereditary glomerulopathies which suggests that AS is often underrecognized. The natural history and prognosis in patients with AS is variable and is determined by genetics and environmental factors. At present, no preventive or curative therapies exist for AS. Current treatment includes the use of renin-angiotensin-aldosterone system inhibitors which slow progression of kidney disease and prolong life expectancy. Ramipril was found in retrospective studies to delay the onset of ESKD and was recently demonstrated to be safe and effective in children and adolescents, supporting that early initiation of Renin Angiotensin Aldosterone System (RAAS) blockade is very important. Mineralocorticoid receptor blockers might be favorable for patients who develop "aldosterone breakthrough." While the DAPA-CKD trial suggests a beneficial effect of SGLT2 inhibitors in CKD of non-metabolic origin, only a handful of patients had Alport in this cohort, and therefore conclusions can't be extrapolated for the treatment of AS with SGLT2 inhibitors. Advances in our understanding on the pathogenesis of Alport syndrome has culminated in the development of innovative therapeutic approaches that are currently under investigation. We will provide a brief overview of novel therapeutic targets to prevent progression of kidney disease in AS. Our review will include bardoxolone methyl, an oral NRf2 activator; lademirsen, an anti-miRNA-21 molecule; sparsentan, dual endothelin type A receptor (ETAR) and angiotensin 1 receptor inhibitor; atrasentan, oral selective ETAR inhibitor; lipid-modifying agents, including cholesterol efflux transporter ATP-binding cassette A1 (ABCA1) inducers, discoidin domain receptor 1 (DDR1) inhibitors and osteopontin blocking agents; the antimalarial drug hydroxychloroquine; the antiglycemic drug metformin and the active vitamin D analog paricalcitol. Future genomic therapeutic strategies such as chaperone therapy, genome editing and stem cell therapy will also be discussed.
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Affiliation(s)
- Efren Chavez
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Juanly Rodriguez
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Yelena Drexler
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Alessia Fornoni
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, United States.,Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of Medicine, Miami, FL, United States
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30
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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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The 2019 and 2021 International Workshops on Alport Syndrome. Eur J Hum Genet 2022; 30:507-516. [PMID: 35260866 PMCID: PMC8904161 DOI: 10.1038/s41431-022-01075-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 02/04/2022] [Accepted: 02/14/2022] [Indexed: 01/27/2023] Open
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Kashtan CE. What the Adult Nephrologist Should Know About Alport Syndrome. Adv Chronic Kidney Dis 2022; 29:225-230. [PMID: 36084969 DOI: 10.1053/j.ackd.2021.08.003] [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: 06/25/2021] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 11/11/2022]
Abstract
Recent trends in the diagnosis, treatment, and classification of collagen IV-associated kidney disease are likely to result in increasing numbers of people in adult nephrology practices who have a confirmed diagnosis of Alport syndrome. These trends include the increasing use of genetic testing in the diagnostic evaluation of people with hematuria, focal segmental glomerulosclerosis, and chronic kidney disease of unknown etiology; early treatment with inhibitors of the renin-angiotensin-aldosterone system to delay kidney failure; and application of an expanded definition of Alport syndrome based on genotype rather than phenotype. This commentary discusses these trends and their implications for the adult nephrologist.
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Affiliation(s)
- Clifford E Kashtan
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN.
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Hu Y, Li W, Tian L, Fu S, Min Y, Liu J, Xiong F. Case Report: Identification of a Novel Heterozygous Missense Mutation in COL4A3 Gene Causing Variable Phenotypes in an Autosomal-Dominant Alport Syndrome Family. Front Genet 2022; 13:839212. [PMID: 35422838 PMCID: PMC9001967 DOI: 10.3389/fgene.2022.839212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 03/04/2022] [Indexed: 12/02/2022] Open
Abstract
Alport syndrome (AS) is a genetic kidney disease of basement membrane collagen disorder accounting for approximately 2% of ESRD patients. Next-generation and whole-exome sequencing methods are increasingly frequently used as an efficient tool not only for the diagnosis of AS but also for the establishment of genotype–phenotype correlation. We herein report the identification of a novel heterozygous missense mutation in COL4A3 gene (c.G3566A: p.G1189E) causing variable phenotypes in an ADAS Family based on the combination of clinical, histologic, pedigree, and genetic sequencing information. The proband is a 48-year-old Chinese woman suffering from persistent subnephrotic proteinuria and intermittent hematuria without renal function impairment over a 10-year time-span. Renal biopsy showed diffuse thin basement membrane and focal interstitial foam cell infiltration. The proband’s mother progressed to end-stage renal failure and the proband’s sister presented with subnephrotic proteinuria and intermittent hematuria as well. AS was highly suspected and confirmed by exome sequencing which revealed a novel heterozygous missense mutation in COL4A3 gene (c.G3566A: p.G1189E) in all the affected family members, although their current medical conditions vary significantly. Our present finding emphasizes the significance of next-generation sequencing technology for genetic screening which gives us an accurate clinical diagnosis of ADAS patients. The identification of c.G3566A as a new ADAS-related mutation contributes to both genetic diagnosis of ADAS and further functional study of COL4A3. The variable phenotypes from the same genotype of our case also provide more information to genotype–phenotype correlation study.
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Affiliation(s)
- Yanglin Hu
- Department of Nephrology, Wuhan No.1 Hospital, Wuhan, China
| | - Wei Li
- Department of Endocrinology, Wuhan No.1 Hospital, Wuhan, China
| | - Lulu Tian
- Department of Blood Purification, Central Theater General Hospital, Wuhan, China
| | - Shuai Fu
- Department of Nephrology, Wuhan No.1 Hospital, Wuhan, China
| | - Yonglong Min
- Department of Nephrology, Wuhan No.1 Hospital, Wuhan, China
| | - Jia Liu
- Department of Nephrology, Wuhan No.1 Hospital, Wuhan, China
| | - Fei Xiong
- Department of Nephrology, Wuhan No.1 Hospital, Wuhan, China
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Abstract
A number of genes that cause inherited kidney disorders reside on the X chromosome. Given that males have only a single active X chromosome, these disorders clinically manifest primarily in men and boys. However, phenotypes in female carriers of X-linked kidney conditions are becoming more and more recognized. This article reviews the biology of X inactivation as well as the kidney phenotype in women and girls with a number of X-linked kidney disorders including Alport syndrome, Fabry disease, nephrogenic diabetes insipidus, X-linked hypophosphatemic rickets, Dent disease, and Lowe syndrome.
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Affiliation(s)
- Catherine Quinlan
- Department of Nephrology, Royal Children's Hospital, Melbourne, Victoria, Australia; Department of Kidney Regeneration, Murdoch Children's Research Institute, Melbourne, Victoria, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Michelle N Rheault
- Division of Pediatric Nephrology, Department of Pediatrics, University of Minnesota Masonic Children's Hospital, Minneapolis, MN.
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Yamamura T, Horinouchi T, Aoto Y, Lennon R, Nozu K. The Contribution of COL4A5 Splicing Variants to the Pathogenesis of X-Linked Alport Syndrome. Front Med (Lausanne) 2022; 9:841391. [PMID: 35211492 PMCID: PMC8861460 DOI: 10.3389/fmed.2022.841391] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 01/10/2022] [Indexed: 11/25/2022] Open
Abstract
X-linked Alport syndrome (XLAS) is caused by pathogenic variants in COL4A5 and is characterized by progressive kidney disease, hearing loss, and ocular abnormalities. Recent advances in genetic analysis and further understanding of genotype-phenotype correlations in affected male patients raises the importance of detecting splicing variants in COL4A5. Aberrant splicing of COL4A5 is caused not only by canonical splice site variants but also non-canonical splice site variants such as deep intronic changes or even substitutions in exons. Patients with splicing variants account for ~15% of all cases in XLAS. In addition, it has been shown that there is a significant difference in kidney survival depending on the aberrant splicing patterns of transcripts- in particular in-frame or out-of-frame nucleotide changes in transcripts. Therefore, cDNA analysis of patient mRNA is necessary to determine the impact of splice site variants and to confirm a diagnosis of XLAS and to predict the kidney prognosis. However, it is usually difficult to amplify COL4A5 transcripts extracted from peripheral blood leukocytes. For these cases, in vitro minigene assays or RNA sequence extracted from urine derived cells can confirm aberrant splicing patterns. Moreover, controlling aberrant splicing by nucleic acids or small molecular compounds in genetic diseases are attracting attention as a potential therapeutic strategy. Here, we review the frequency of splicing variants in COL4A5, the latest diagnostic strategies, and the prospects for new therapeutic approaches.
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Affiliation(s)
- Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.,Wellcome Centre for Cell-Matrix Research, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Rachel Lennon
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom.,Department of Paediatric Nephrology, Royal Manchester Children's Hospital, Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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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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37
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Omachi K, Kai H, Roberge M, Miner JH. Full-length and split-NanoLuc reporters identify pathogenic COL4A5 nonsense mutations susceptible to premature termination codon readthrough. iScience 2022; 25:103891. [PMID: 35243249 PMCID: PMC8866893 DOI: 10.1016/j.isci.2022.103891] [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] [Received: 07/25/2021] [Revised: 12/22/2021] [Accepted: 02/04/2022] [Indexed: 11/02/2022] Open
Abstract
Alport syndrome, a disease of kidney, ear, and eye, is caused by pathogenic variants in the COL4A3, COL4A4, or COL4A5 genes encoding collagen α3α4α5(IV) of basement membranes. Collagen IV chains that are truncated due to nonsense variants/premature termination codons (PTCs) cannot assemble into heterotrimers or incorporate into basement membranes. To investigate the feasibility of PTC readthrough therapy for Alport syndrome, we utilized two NanoLuc reporters in transfected cells: full-length for monitoring translation, and a split version for assessing readthrough product function. Full-length assays of 49 COL4A5 nonsense variants identified eleven as susceptible to PTC readthrough using various readthrough drugs. In split-NanoLuc assays, the predicted missense α5(IV) readthrough products of five nonsense mutations could heterotrimerize with α3(IV) and α4(IV). Readthrough was also observed in kidney cells from an engineered Col4a5 PTC mouse model. These results suggest that readthrough therapy is a feasible approach for a fraction of patients with Alport syndrome. NanoLuc fusion constructs identified COL4A5 mutants susceptible to PTC readthrough Readthrough enhancer and “designer” compounds promoted PTC readthrough Split-NanoLuc fusion constructs identified functional missense readthrough products Cultured Col4a5 nonsense mutant mouse kidney cells were susceptible to readthrough
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38
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Aoto Y, Horinouchi T, Yamamura T, Kondo A, Nagai S, Ishiko S, Okada E, Rossanti R, Sakakibara N, Nagano C, Awano H, Nagase H, Shima Y, Nakanishi K, Matsuo M, Iijima K, Nozu K. Last Nucleotide Substitutions of COL4A5 Exons Cause Aberrant Splicing. Kidney Int Rep 2022; 7:108-116. [PMID: 35005319 PMCID: PMC8720670 DOI: 10.1016/j.ekir.2021.10.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/08/2021] [Accepted: 10/11/2021] [Indexed: 12/23/2022] Open
Abstract
Introduction COL4A5 is a causative gene of X-linked Alport syndrome (XLAS). Male patients with XLAS with nonsense variants have the most severe phenotypes of early onset end-stage kidney disease (ESKD); those with splicing variants have middle phenotypes and those with missense variants have the mildest phenotypes. Therefore, genotyping for male patients with XLAS can be used to predict kidney prognosis. Single-base substitutions at the last nucleotide position in each exon are known to affect splicing patterns and could be splicing variants. Nevertheless, in XLAS, these variants are generally considered to be missense variants, without conducting a transcript analysis, which underestimates some patients as having mild phenotypes. This study aimed to investigate whether single-base substitutions at the last nucleotide position of COL4A5 exons cause aberrant splicing. Methods In total, 20 variants were found in the Human Gene Mutation Database (n = 14) and our cohort (n = 6). We performed functional splicing assays using a hybrid minigene analysis and in vivo transcript analyses of patients’ samples when available. Then, we investigated genotype–phenotype correlations for patients with splicing variants detected in this study by comparing data from our previous studies. Results Among the 20 variants, 17 (85%) caused aberrant splicing. Male patients with splicing variants had more severe phenotypes when compared with those with missense variants. Findings from the in vivo analyses for 3 variants were identical to those from the minigene assay. Conclusion Our study revealed that most single-base substitutions at the last nucleotide position of COL4A5 exons result in splicing variants, rather than missense variants, thereby leading to more severe phenotypes.
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Affiliation(s)
- Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - 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
| | - Atsushi Kondo
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Sadayuki Nagai
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Eri Okada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroyuki Awano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroaki Nagase
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, 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, Okinawa, Japan
| | - Masafumi Matsuo
- Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan
| | - Kazumoto Iijima
- Hyogo Prefectural Kobe Children's Hospital, Hyogo, Japan.,Department of Advanced Pediatric Medicine, Kobe University Graduate School of Medicine, Hyogo, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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39
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Morais MRPT, Tian P, Lawless C, Murtuza-Baker S, Hopkinson L, Woods S, Mironov A, Long DA, Gale DP, Zorn TMT, Kimber SJ, Zent R, Lennon R. Kidney organoids recapitulate human basement membrane assembly in health and disease. eLife 2022; 11:73486. [PMID: 35076391 PMCID: PMC8849328 DOI: 10.7554/elife.73486] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 01/24/2022] [Indexed: 12/04/2022] Open
Abstract
Basement membranes (BMs) are complex macromolecular networks underlying all continuous layers of cells. Essential components include collagen IV and laminins, which are affected by human genetic variants leading to a range of debilitating conditions including kidney, muscle, and cerebrovascular phenotypes. We investigated the dynamics of BM assembly in human pluripotent stem cell-derived kidney organoids. We resolved their global BM composition and discovered a conserved temporal sequence in BM assembly that paralleled mammalian fetal kidneys. We identified the emergence of key BM isoforms, which were altered by a pathogenic variant in COL4A5. Integrating organoid, fetal, and adult kidney proteomes, we found dynamic regulation of BM composition through development to adulthood, and with single-cell transcriptomic analysis we mapped the cellular origins of BM components. Overall, we define the complex and dynamic nature of kidney organoid BM assembly and provide a platform for understanding its wider relevance in human development and disease.
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Affiliation(s)
- Mychel RPT Morais
- Wellcome Trust Centre for Cell-Matrix Research, University of ManchesterManchesterUnited Kingdom
| | - Pinyuan Tian
- Wellcome Trust Centre for Cell-Matrix Research, University of ManchesterManchesterUnited Kingdom
| | - Craig Lawless
- Wellcome Trust Centre for Cell-Matrix Research, University of ManchesterManchesterUnited Kingdom
| | - Syed Murtuza-Baker
- Division of Informatics, Imaging and Data Sciences, University of ManchesterManchesterUnited Kingdom
| | - Louise Hopkinson
- Wellcome Trust Centre for Cell-Matrix Research, University of ManchesterManchesterUnited Kingdom
| | - Steven Woods
- Division of Cell Matrix Biology and Regenerative Medicine, University of ManchesterManchesterUnited Kingdom
| | - Aleksandr Mironov
- Electron Microscopy Core Facility, University of ManchesterManchesterUnited Kingdom
| | - David A Long
- Developmental Biology and Cancer Programme, University College LondonLondonUnited Kingdom
| | - Daniel P Gale
- Department of Renal Medicine, University College LondonLondonUnited Kingdom
| | - Telma MT Zorn
- Department of Cell and Developmental Biology, University of São PauloSão PauloBrazil
| | - Susan J Kimber
- Division of Cell Matrix Biology and Regenerative Medicine, University of ManchesterManchesterUnited Kingdom
| | - Roy Zent
- Department of Medicine, Vanderbilt University Medical CenterNashvilleUnited States
| | - Rachel Lennon
- Wellcome Trust Centre for Cell-Matrix Research, University of ManchesterManchesterUnited Kingdom,Department of Paediatric Nephrology, Royal Manchester Children’s Hospital, Manchester University Hospitals NHS Foundation TrustManchesterUnited Kingdom
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40
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Qian P, Bao Y, Huang HM, Suo L, Han Y, Li ZJ, Zhang M. A deep intronic splice variant of the COL4A5 gene in a Chinese family with X-linked Alport syndrome. Front Pediatr 2022; 10:1009188. [PMID: 36714647 PMCID: PMC9880855 DOI: 10.3389/fped.2022.1009188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 12/26/2022] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND X-linked Alport syndrome (XLAS) is caused by pathogenic variants in COL4A5 and is characterized by progressive kidney disease, hearing loss, and ocular abnormalities.The aim of this study was to identify gene mutations in a Chinese family with XLAS, confirm a diagnosis, and provide an accurate genetic counseling. METHODS The proband was a 5-year-old male with microscopic hematuria and a family history of renal disease in 5 relatives.His relatives had microhematuria with or without proteinuria. His maternal uncle developed renal failure at the age of 35 years. He was evaluated by renal biopsy,whole-exome sequencing (WES) and whole-genome sequencing (WGS) for Alport syndrome. RT-PCR and cDNA Sanger sequencing were performed on RNA extracted from the skin of the proband. Then, a splicing reporter minigene assay was used to examine the effect of the variation on the splicing of the primary transcript in transfected cells. RESULTS Pathological examination of the kidney of the proband revealed diffuse thinning of the glomerular basement membrane, and immunofluorescence analysis indicated normal expression of the α5 chain in the basement membrane. No phenotype-associated candidate variant was detected in the proband via WES. A novel deep intronic COL4A5 variant (c.385-716G > A), which is segregated with disease in this family, was identified using WGS. In-vitro minigene assay and in-vivo RT-PCR analysis demonstrated that the variant could produce both normal and abnormal transcripts. The abnormal transcripts showed that the variant activated a cryptic splice site, introducing a 147 bp pseudoexon into the mRNA sequence and consequently generating a premature termination codon (p.G129Afs*38) and leading to frameshifting and truncation of the α5 (collagen IV) protein. CONCLUSION This is the first report of the novel c.385-716G > A splicing mutation in the COL4A5 gene, which illustrates the importance of performing WGS to find additional mutations in WES-negative patients with highly suspected forms of genetic diseases. The same results obtained from the in-vitro and in-vivo splicing experiments confirm the consistency between the minigene assay and RT-PCR analysis. In addition, this study highlights the importance of functional analysis in diagnosis and genetic counseling in AS.
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Affiliation(s)
- Pei Qian
- Department of Nephrology, Xi'an Children's Hospital, Xi'an, China
| | - Ying Bao
- Department of Nephrology, Xi'an Children's Hospital, Xi'an, China
| | - Hui-Mei Huang
- Department of Nephrology, Xi'an Children's Hospital, Xi'an, China
| | - Lei Suo
- Department of Nephrology, Xi'an Children's Hospital, Xi'an, China
| | - Yan Han
- Department of Nephrology, Xi'an Children's Hospital, Xi'an, China
| | - Zhi-Juan Li
- Department of Nephrology, Xi'an Children's Hospital, Xi'an, China
| | - Min Zhang
- Department of Nephrology, Xi'an Children's Hospital, Xi'an, China
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41
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Jayasinghe K, Wu Y, Stark Z, Kerr PG, Mallett AJ, Gaff C, Martyn M, Goranitis I, Quinlan C. Cost-Effectiveness of Targeted Exome Analysis as a Diagnostic Test in Glomerular Diseases. Kidney Int Rep 2021; 6:2850-2861. [PMID: 34805637 PMCID: PMC8589690 DOI: 10.1016/j.ekir.2021.08.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 08/12/2021] [Accepted: 08/30/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Despite the emergence of diagnostic and clinical utility evidence in nephrology, publicly funded access to genomic testing is restricted in most health care systems. To establish genomic sequencing as a clinical test, an evaluation of cost-effectiveness is urgently required. METHODS An economic evaluation, informed by a primary clinical study and available clinical evidence and guidelines in nephrology, was performed to evaluate the cost-effectiveness and optimal timing of exome sequencing (ES) in adults and children with suspected monogenic glomerular diseases compared with nongenomic investigations (NGIs). Six diagnostic strategies reflecting current practice and recommended models of care in Australia were modeled: (i) NGIs, (ii) late gene panel followed by ES, (iii) late ES, (iv) early gene panel, (v) early gene panel followed by ES, and (vi) early ES. RESULTS ES with targeted analysis achieved a diagnosis in 23 of 63 (36.5%) adults and 10 of 24 (41.6%) children. NGIs were estimated to diagnose 4.0% of children, with an average estimated cost of AU$6120 per child. Integrating ES as a first-line test in children was cost saving, with an incremental cost saving of AU$3230 per additional diagnosis compared with NGIs. In adults, NGIs was estimated to diagnose 8% of patients, with an average estimated cost of AU$1830 per person. In adults, integrating ES early resulted in an incremental cost per additional diagnosis of AU$5460 relative to NGIs. CONCLUSIONS Early ES with targeted analysis was effective for diagnosing monogenic kidney disease, with substantial cost savings in children.
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Affiliation(s)
- Kushani Jayasinghe
- Department of Nephrology, Monash Medical Centre, Melbourne, Australia
- Monash University, Melbourne, Australia
- Murdoch Children’s Research Institute, Melbourne, Australia
- The KidGen Collaborative, Australian Genomics Health Alliance, Melbourne, Australia
| | - You Wu
- Centre for Health Policy, University of Melbourne, Melbourne, VIC, Australia
- Australian Genomics Health Alliance, Melbourne, VIC, Australia
| | - Zornitza Stark
- Murdoch Children’s Research Institute, Melbourne, Australia
- The KidGen Collaborative, Australian Genomics Health Alliance, Melbourne, Australia
- Department of Pediatrics, University of Melbourne, Australia
- Victorian Clinical Genetics Services, Melbourne, Australia
| | - Peter G. Kerr
- Department of Nephrology, Monash Medical Centre, Melbourne, Australia
- Monash University, Melbourne, Australia
| | - Andrew J. Mallett
- The KidGen Collaborative, Australian Genomics Health Alliance, Melbourne, Australia
- Department of Renal Medicine, Townsville University Hospital, Townsville, QLD, Australia
- College of Medicine and Dentistry, James Cook University, Townsville, QLD, Australia
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Clara Gaff
- Department of Pediatrics, University of Melbourne, Australia
- Melbourne Genomics Health Alliance, Melbourne, Australia
| | - Melissa Martyn
- Murdoch Children’s Research Institute, Melbourne, Australia
- Melbourne Genomics Health Alliance, Melbourne, Australia
| | - Ilias Goranitis
- Centre for Health Policy, University of Melbourne, Melbourne, VIC, Australia
- Australian Genomics Health Alliance, Melbourne, VIC, Australia
| | - Catherine Quinlan
- Murdoch Children’s Research Institute, Melbourne, Australia
- The KidGen Collaborative, Australian Genomics Health Alliance, Melbourne, Australia
- Department of Pediatrics, University of Melbourne, Australia
- Department of Pediatric Nephrology, Royal Children’s Hospital, Melbourne, Australia
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Family Genetic Screening to Identify Cases of Alport Syndrome: A Case Study Report. Kidney Med 2021; 3:866-867. [PMID: 34693267 PMCID: PMC8515063 DOI: 10.1016/j.xkme.2021.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Martínez-Pulleiro R, García-Murias M, Fidalgo-Díaz M, García-González MÁ. Molecular Basis, Diagnostic Challenges and Therapeutic Approaches of Alport Syndrome: A Primer for Clinicians. Int J Mol Sci 2021; 22:ijms222011063. [PMID: 34681722 PMCID: PMC8541626 DOI: 10.3390/ijms222011063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/06/2021] [Accepted: 10/11/2021] [Indexed: 12/20/2022] Open
Abstract
Alport syndrome is a genetic and hereditary disease, caused by mutations in the type IV collagen genes COL4A3, COL4A4 and COL4A5, that affects the glomerular basement membrane of the kidney. It is a rare disease with an underestimated prevalence. Genetic analysis of population cohorts has revealed that it is the second most common inherited kidney disease after polycystic kidney disease. Renal involvement is the main manifestation, although it may have associated extrarenal manifestations such as hearing loss or ocular problems. The degree of expression of the disease changes according to the gene affected and other factors, known or yet to be known. The pathophysiology is not yet fully understood, although some receptors, pathways or molecules are known to be linked to the disease. There is also no specific treatment for Alport syndrome; the most commonly used are renin–angiotensin–aldosterone system inhibitors. In recent years, diagnosis has come a long way, thanks to advances in DNA sequencing technologies such as next-generation sequencing (NGS). Further research at the genetic and molecular levels in the future will complete the partial vision of the pathophysiological mechanism that we have, and will allow us to better understand what is happening and how to solve it.
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Affiliation(s)
- Raquel Martínez-Pulleiro
- Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxía (No. 11), Instituto de Investigación Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain; (R.M.-P.); (M.G.-M.)
- Grupo de Medicina Xenómica (GMX), 15706 Santiago de Compostela, Spain
| | - María García-Murias
- Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxía (No. 11), Instituto de Investigación Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain; (R.M.-P.); (M.G.-M.)
- Grupo de Medicina Xenómica (GMX), 15706 Santiago de Compostela, Spain
| | - Manuel Fidalgo-Díaz
- Departamento de Nefrología, Complexo Hospitalario Universitario de Santiago (CHUS), 15706 Santiago de Compostela, Spain;
| | - Miguel Ángel García-González
- Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxía (No. 11), Instituto de Investigación Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain; (R.M.-P.); (M.G.-M.)
- Grupo de Medicina Xenómica (GMX), 15706 Santiago de Compostela, Spain
- Fundación Pública Galega de Medicina Xenómica-SERGAS, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
- Correspondence: ; Tel.: +34-981-555-197
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Quinlan C, Rheault MN. Genetic Basis of Type IV Collagen Disorders of the Kidney. Clin J Am Soc Nephrol 2021; 16:1101-1109. [PMID: 33849932 PMCID: PMC8425620 DOI: 10.2215/cjn.19171220] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The glomerular basement membrane is a vital component of the filtration barrier of the kidney and is primarily composed of a highly structured matrix of type IV collagen. Specific isoforms of type IV collagen, the α3(IV), α4(IV), and α5(IV) isoforms, assemble into trimers that are required for normal glomerular basement membrane function. Disruption or alteration in these isoforms leads to breakdown of the glomerular basement membrane structure and function and can lead to progressive CKD known as Alport syndrome. However, there is wide variability in phenotype among patients with mutations affecting type IV collagen that depends on a complex interplay of sex, genotype, and X-chromosome inactivation. This article reviews the genetic basis of collagen disorders of the kidney as well as potential treatments for these conditions, including direct alteration of the DNA, RNA therapies, and manipulation of collagen proteins.
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Affiliation(s)
- Catherine Quinlan
- Department of Nephrology, Royal Children’s Hospital, Melbourne, Victoria, Australia,Department of Kidney Regeneration, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Michelle N. Rheault
- Division of Pediatric Nephrology, Department of Pediatrics, University of Minnesota Masonic Children’s Hospital, Minneapolis, Minnesota
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Rubel D, Zhang Y, Sowa N, Girgert R, Gross O. Organoprotective Effects of Spironolactone on Top of Ramipril Therapy in a Mouse Model for Alport Syndrome. J Clin Med 2021; 10:jcm10132958. [PMID: 34209341 PMCID: PMC8268845 DOI: 10.3390/jcm10132958] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 06/17/2021] [Accepted: 06/29/2021] [Indexed: 12/27/2022] Open
Abstract
Angiotensin-converting enzyme inhibitors (ACEi) delay progression of the inherited renal disease Alport syndrome. However, the effect of ACEis weakens gradually due to an “aldosterone escape”. Here, we investigate if an aldosterone antagonist can counteract loss of ACEi-efficacy. COL4A3−/− mice were treated with ramipril (ACEi), starting at 4.5 weeks of age, and spironolactone was added at 7 weeks of age. Lifespan until renal failure, as well as kidney function parameters, were investigated. Dual therapy decreased proteinuria levels compared to ACEi monotherapy. Matrix accumulation, as well as tubulointerstitial and glomerular scar-tissue formation, were significantly reduced compared to untreated mice and ACEi-monotherapy at 75 and 100 days. Lifespan in dual treated mice was extended compared to untreated mice. However, lifespan was not superior to ACEi monotherapy–despite improved urea-nitrogen levels in the dual therapy group. In conclusion, adding the aldosterone-antagonist spironolactone to ACEi therapy further improved kidney function and reduced proteinuria and fibrosis. However, survival was not improved further, possibly due to premature death from side effects of dual therapy such as hyperkalemia. Thus, dual therapy could offer an effective therapy option for Alport syndrome patients with progressive proteinuria. However, the risks of adverse events require close monitoring.
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Affiliation(s)
- Diana Rubel
- Clinic of Nephrology and Rheumatology, University Medical Center Goettingen, 37075 Goettingen, Germany; (D.R.); (Y.Z.); (N.S.); (R.G.)
| | - Yanqin Zhang
- Clinic of Nephrology and Rheumatology, University Medical Center Goettingen, 37075 Goettingen, Germany; (D.R.); (Y.Z.); (N.S.); (R.G.)
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Nenja Sowa
- Clinic of Nephrology and Rheumatology, University Medical Center Goettingen, 37075 Goettingen, Germany; (D.R.); (Y.Z.); (N.S.); (R.G.)
| | - Rainer Girgert
- Clinic of Nephrology and Rheumatology, University Medical Center Goettingen, 37075 Goettingen, Germany; (D.R.); (Y.Z.); (N.S.); (R.G.)
| | - Oliver Gross
- Clinic of Nephrology and Rheumatology, University Medical Center Goettingen, 37075 Goettingen, Germany; (D.R.); (Y.Z.); (N.S.); (R.G.)
- Correspondence: ; Tel.: +49-551-60488
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Kashtan C. Multidisciplinary Management of Alport Syndrome: Current Perspectives. J Multidiscip Healthc 2021; 14:1169-1180. [PMID: 34045864 PMCID: PMC8149282 DOI: 10.2147/jmdh.s284784] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 04/30/2021] [Indexed: 12/11/2022] Open
Abstract
Alport syndrome is a multisystem disorder that universally affects the kidney and frequently involves the inner ear and the eye. Over the course of a lifetime, addressing the health care needs of a person with Alport syndrome and their family entails the services of primary providers, nephrologists, genetic counselors, audiologists, ophthalmologists, transplant physicians, kidney dieticians, and social workers as well as other healthcare professionals. This article attempts to provide context and guidance regarding the multidisciplinary care of Alport syndrome based on the natural history of the condition.
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Affiliation(s)
- Clifford Kashtan
- Department of Pediatrics, Division of Pediatric Nephrology, University of Minnesota Medical School, Minneapolis, MN, 55454, USA
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Kashtan CE, Gross O. Clinical practice recommendations for the diagnosis and management of Alport syndrome in children, adolescents, and young adults-an update for 2020. Pediatr Nephrol 2021; 36:711-719. [PMID: 33159213 DOI: 10.1007/s00467-020-04819-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/24/2020] [Accepted: 10/08/2020] [Indexed: 12/28/2022]
Abstract
In 2013, we published a set of clinical practice recommendations for the treatment of Alport syndrome in this journal. We recommended delaying the initiation of angiotensin-converting enzyme inhibition until the onset of overt proteinuria or, in some cases, microalbuminuria. Developments that have occurred over the past 7 years have prompted us to revise these recommendations. We now recommend the initiation of treatment at the time of diagnosis in males with X-linked Alport syndrome and in males and females with autosomal recessive Alport syndrome. We further recommend starting treatment at the onset of microalbuminuria in females with X-linked Alport syndrome and in males and females with autosomal dominant Alport syndrome. This article presents the rationale for these revisions as well as recommendations for diagnostic tactics intended to ensure the early diagnosis of Alport syndrome.
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Affiliation(s)
- Clifford E Kashtan
- Department of Pediatrics, Division of Pediatric Nephrology, University of Minnesota Medical School, 2450 Riverside Avenue, Minneapolis, MN, 55454, USA.
| | - Oliver Gross
- Department of Nephrology and Rheumatology, University Medical Center Goettingen, Goettingen, Germany
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Genotype-phenotype correlations and nephroprotective effects of RAAS inhibition in patients with autosomal recessive Alport syndrome. Pediatr Nephrol 2021; 36:2719-2730. [PMID: 33772369 PMCID: PMC8370956 DOI: 10.1007/s00467-021-05040-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 02/20/2021] [Accepted: 03/02/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND Autosomal recessive Alport syndrome (ARAS) is caused by pathogenic variants in both alleles of either COL4A3 or COL4A4 genes. Reports on ARAS are rare due to small patient numbers and there are no reports on renin-angiotensin-aldosterone system (RAAS) inhibition therapy in ARAS. METHODS Retrospective study in 101 patients with ARAS from Chinese Registry Database of Hereditary Kidney Diseases and European Alport Registry. Genotype-phenotype correlations and nephroprotective effects of RAAS inhibition in ARAS were evaluated. RESULTS Median age was 15 years (range 1.5-46 years). Twelve patients progressed to stage 5 chronic kidney disease (CKD5) at median age 20.5 years. Patients without missense variants had both higher prevalence and earlier onset age of hearing loss, nephrotic-range proteinuria, more rapid decline of eGFR, and earlier onset age of CKD5 compared to patients with 1 or 2 missense variants. Most patients (79/101, 78%) currently are treated with RAAS inhibitors; median age at therapy initiation was 10 years and mean duration 6.5 ± 6.0 years. Median age at CKD5 for untreated patients was 24 years. RAAS inhibition therapy delayed CKD5 onset in those with impaired kidney function (T-III) to median age 35 years, but is undefined in treated patients with proteinuria (T-II) due to low number of events. No treated patients with microalbuminuria (T-I) progressed to CKD5. ARAS patients with 1 or 2 missense variants showed better response to treatment than patients with non-missense-variants. CONCLUSIONS Our study provides the first evidence for early use of RAAS inhibition therapy in patients with ARAS. Furthermore, genotype in ARAS correlates with response to therapy in favor of missense variants.
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Angiotensin-converting enzyme inhibitors in patients with Alport syndrome: can all patients benefit? Kidney Int 2020; 98:1400-1402. [PMID: 33276866 DOI: 10.1016/j.kint.2020.07.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 07/23/2020] [Indexed: 12/22/2022]
Abstract
Angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs) are prescribed to slow the progression of kidney disease in patients with Alport syndrome. In a recent publication by Yamamura et al. the authors showed an association of ACEi or ARB treatment with delay in ESKD, even for those patients with severe, truncating mutations. Despite these encouraging findings, there remain a number of clinical questions about the use of ACEi and ARBs in Alport syndrome.
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