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Younsi ME, Achour A, Kraoua L, Nesrine M, Sayari T, Abderrahim E, Laabidi J, Zouaghi MK, Kharrat M, Gargah T, Trabelsi M, M'rad R. Genetic study of Alport syndrome in Tunisia. Pediatr Nephrol 2024:10.1007/s00467-024-06474-7. [PMID: 39138691 DOI: 10.1007/s00467-024-06474-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 06/13/2024] [Accepted: 07/11/2024] [Indexed: 08/15/2024]
Abstract
BACKGROUND Alport syndrome is a genetic disorder affecting the kidneys, ears, and eyes, causing chronic kidney disease, sensorineural hearing loss, and ocular abnormalities. It results from pathogenic variants in the COL4A3, COL4A4, or COL4A5 genes, with different inheritance patterns: X-linked from COL4A5 variants, autosomal recessive from homozygous variants in COL4A3 or COL4A4, digenic from variants in both COL4A3 and COL4A4, and autosomal dominant from heterozygous variants in COL4A3 or COL4A4. METHODS We analyzed 45 patients with Alport syndrome from 11 Tunisian families to determine their clinical and genetic characteristics. Clinical data were collected retrospectively, and whole-exome sequencing was conducted on one patient from each family. Sanger sequencing validated pathogenic variants, and cascade screening extended the analysis to 53 individuals. RESULTS We identified nine likely pathogenic variants among 11 index cases: six novel and three known variations. Of these, five were in COL4A3, and four were in COL4A5, with variants including frameshift, nonsense, missense, and alternative splicing. Most variations affected the Gly-XY codon. Among the 45 clinically identified siblings, 30 tested positive for Alport syndrome. The cascade screening identified 3 additional affected individuals, 10 unaffected siblings, and 10 unaffected parents. The mode of inheritance was autosomal recessive in six families and X-linked in four families. CONCLUSIONS This study is the first to screen the mutational spectrum of Alport syndrome in Tunisia. It reveals novel pathogenic variants and suggests that autosomal recessive inheritance may be more common in the Tunisian population than X-linked inheritance, contrary to existing literature.
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Affiliation(s)
- Mariem El Younsi
- Laboratoire de Génétique Humaine, Faculté de Médecine de Tunis, Université de Tunis El Manar, LR99ES101007, Tunis, Tunisia
| | - Ahlem Achour
- Laboratoire de Génétique Humaine, Faculté de Médecine de Tunis, Université de Tunis El Manar, LR99ES101007, Tunis, Tunisia
- Service des Maladies Congénitales Et Héréditaires, Hôpital Charles Nicolle, 1006, Tunis, Tunisia
| | - Lilia Kraoua
- Laboratoire de Génétique Humaine, Faculté de Médecine de Tunis, Université de Tunis El Manar, LR99ES101007, Tunis, Tunisia
- Service des Maladies Congénitales Et Héréditaires, Hôpital Charles Nicolle, 1006, Tunis, Tunisia
| | - Mezzi Nesrine
- Laboratory of Biomedical Genomics and Oncogenetics, Pasteur Institute of Tunis, 1002, Tunis, Tunisia
| | - Taha Sayari
- Service de Néphrologie Pédiatrique, Hôpital Charles Nicolle, 1006, Tunis, Tunisia
| | - Ezzeddine Abderrahim
- Service de Médecine Interne Et de Néphrologie Adulte, Hôpital Charles Nicolle, 1006, Tunis, Tunisia
| | - Janet Laabidi
- Service Néphrologie, L'Hôpital Militaire Principal d'Instruction de Tunis, MontFleury, 1008, Tunis, Tunisia
| | - Mohamed Karim Zouaghi
- Service de Néphrologie, Dialyse Et Transplantation Rénale, Hôpital La Rabta 1007, Tunis, Tunisia
| | - Maher Kharrat
- Laboratoire de Génétique Humaine, Faculté de Médecine de Tunis, Université de Tunis El Manar, LR99ES101007, Tunis, Tunisia
| | - Tahar Gargah
- Service de Néphrologie Pédiatrique, Hôpital Charles Nicolle, 1006, Tunis, Tunisia
| | - Mediha Trabelsi
- Laboratoire de Génétique Humaine, Faculté de Médecine de Tunis, Université de Tunis El Manar, LR99ES101007, Tunis, Tunisia
- Service des Maladies Congénitales Et Héréditaires, Hôpital Charles Nicolle, 1006, Tunis, Tunisia
| | - Ridha M'rad
- Laboratoire de Génétique Humaine, Faculté de Médecine de Tunis, Université de Tunis El Manar, LR99ES101007, Tunis, Tunisia.
- Service des Maladies Congénitales Et Héréditaires, Hôpital Charles Nicolle, 1006, Tunis, Tunisia.
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Zellers M, Solanki K, Kelly M, Murphy K, Retterer K, Kirchner HL, Bucaloiu ID, Moore B, Mirshahi T, Chang AR. Genotype-first analysis in an unselected health system-based population reveals variable phenotypic severity of COL4A5 variants. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.06.04.24308453. [PMID: 38883771 PMCID: PMC11177927 DOI: 10.1101/2024.06.04.24308453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
INTRODUCTION Our knowledge of X-linked Alport Syndrome [AS] comes mostly from selected cohorts with more severe disease. METHODS We examined the phenotypic spectrum of X-linked AS in males and females with a genotype-based approach using data from the Geisinger MyCode DiscovEHR study, an unselected health system-based cohort with exome sequencing and electronic health records. Patients with COL4A5 variants reported as pathogenic (P) or likely pathogenic (LP) in ClinVar, or protein-truncating variants (PTVs), were each matched with up to 5 controls without COL4A3/4/5 variants by sociodemographics, diabetes diagnosis, and year of first outpatient encounter. AS-related phenotypes included dipstick hematuria, bilateral sensorineural hearing loss (BSHL), proteinuria, decreased eGFR, and ESKD. RESULTS Out of 170,856 patients, there were 29 hemizygous males (mean age 52.0 y [SD 20.0]) and 55 heterozygous females (mean age 59.3 y [SD 18.8]) with a COL4A5 P/LP variant, including 48 with the hypomorphic variant p.Gly624Asp. Overall, penetrance (having any AS phenotypic feature) was highest for non-p.Gly624Asp P/LP variants (males: 94%, females: 85%), intermediate for p.Gly624Asp (males: 77%, females: 69%), compared to controls (males: 32%; females: 50%). The proportion with ESKD was highest for males with P/LP variants (44%), intermediate for males with p.Gly624Asp (15%) and females with P/LP variants (10%), compared to controls (males: 3%, females 2%). Only 47% of individuals with COL4A5 had completed albuminuria screening, and a minority were taking renin-angiotensin aldosterone system (RAAS) inhibitors. Only 38% of males and 16% of females had a known diagnosis of Alport syndrome or thin basement membrane disease. CONCLUSION In an unselected cohort, we show increased risks of AS-related phenotypes in men and women compared to matched controls, while showing a wider spectrum of severity than has been described previously and variability by genotype. Future studies are needed to determine whether early genetic diagnosis can improve outcomes in Alport Syndrome.
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Gale DP, Gross O, Wang F, Esteban de la Rosa RJ, Hall M, Sayer JA, Appel G, Hariri A, Liu S, Maski M, Shen Y, Zhang Q, Iqbal S, Kowthalam MU, Lin J, Ding J. A Randomized Controlled Clinical Trial Testing Effects of Lademirsen on Kidney Function Decline in Adults with Alport Syndrome. Clin J Am Soc Nephrol 2024; 19:995-1004. [PMID: 38829703 PMCID: PMC11321738 DOI: 10.2215/cjn.0000000000000458] [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: 10/09/2023] [Accepted: 04/29/2024] [Indexed: 06/05/2024]
Abstract
Key Points Lademirsen, an anti–microRNA-21 therapy, was generally well-tolerated in adults with Alport syndrome at risk of rapid disease progression. There were no significant differences between lademirsen-treated and placebo-treated participants in eGFR at any timepoint. The proportions of participants with prespecified reductions in eGFR at weeks 24 and 48 were not significantly different for lademirsen versus placebo. Background Preclinical models of disease have suggested that targeting microRNA-21 (miRNA-21) may slow the decline in kidney function in individuals with Alport syndrome (AS). The objective of this study was to investigate the effects of the anti–miRNA-21 oligonucleotide, lademirsen, on rate of eGFR decline in adults with AS at risk of rapid disease progression. Methods This study was a phase 2 trial of lademirsen, with a randomized, double-blind, placebo-controlled period followed by an open-label period. Adults with AS, eGFR >35 to <90 ml/min per 1.73 m2, and evidence of rapidly progressive kidney dysfunction were randomized 2:1 to lademirsen 110 mg subcutaneously once weekly or placebo for 48 weeks. After a planned interim analysis (after 24 of 43 randomized participants completed the week 48 study visit or discontinued before week 48), the trial was terminated for futility. Results Forty-three adults with AS (26 men, 17 women) participated (mean age 34 years), and 28 (lademirsen: n =19; placebo: n =9) completed 48 weeks of double-blind treatment. All participants in both groups developed treatment-emergent adverse events, mainly respiratory tract infections, headache, dizziness, metabolic/electrolyte disturbances, and anemia. Treatment was discontinued in three lademirsen-treated participants in the double-blind period and one participant in the open-label period, owing to treatment-emergent adverse events. The least squares mean eGFR slope (95% confidence interval) over 48 weeks in the lademirsen and placebo groups was −5 (−8.7 to −1.1) and −5 (−10.2 to 0.8) ml/min per 1.73 m2 per year, respectively. No significant differences between groups were identified in eGFR at any timepoint or in proportion of participants with prespecified reductions in eGFR at week 24 or 48. Conclusions While anti–miRNA-21 therapy with lademirsen was generally well-tolerated with an acceptable safety profile, no meaningful improvement in rate of kidney function decline in adults with AS at risk of rapidly progressive disease was observed. Clinical Trial registration number: NCT02855268 .
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Affiliation(s)
- Daniel P. Gale
- Department of Renal Medicine, University College London, London, United Kingdom
- Royal Free Hospital London, London, United Kingdom
- Great Ormond Street Hospital, London, United Kingdom
| | - Oliver Gross
- Clinic for Nephrology and Rheumatology, University Medicine Göttingen, Göttingen, Germany
| | - Fang Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | | | - Matthew Hall
- Nottingham University Hospitals, Nottingham, United Kingdom
| | - John A. Sayer
- Translational and Clinical Research Institute, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom
| | - Gerald Appel
- Columbia University Medical Center, New York, New York
| | - Ali Hariri
- Eloxx Pharmaceuticals, Watertown, Massachusetts
| | | | | | | | - Qi Zhang
- Sanofi, Cambridge, Massachusetts
| | | | | | | | - Jie Ding
- Department of Pediatrics, Peking University First Hospital, Beijing, China
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Weinstock BA. Lessons Learned from HERA: the First Alport Syndrome Therapeutic Clinical Trial. Clin J Am Soc Nephrol 2024; 19:946-948. [PMID: 38902862 PMCID: PMC11321724 DOI: 10.2215/cjn.0000000000000506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
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Blasco M, Quiroga B, García-Aznar JM, Castro-Alonso C, Fernández-Granados SJ, Luna E, Fernández Fresnedo G, Ossorio M, Izquierdo MJ, Sanchez-Ospina D, Castañeda-Infante L, Mouzo R, Cao M, Besada-Cerecedo ML, Pan-Lizcano R, Torra R, Ortiz A, de Sequera P. Genetic Characterization of Kidney Failure of Unknown Etiology in Spain: Findings From the GENSEN Study. Am J Kidney Dis 2024:S0272-6386(24)00844-8. [PMID: 38972501 DOI: 10.1053/j.ajkd.2024.04.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 04/17/2024] [Accepted: 04/30/2024] [Indexed: 07/09/2024]
Abstract
RATIONALE & OBJECTIVE Chronic kidney disease of unknown etiology (CKDUE) is one of the main global causes of kidney failure. Genetic studies may identify an etiology in these patients, but few studies have implemented genetic testing of CKDUE in a population-based series of patients, which was the focus of the GENSEN Study. STUDY DESIGN Case series. SETTINGS & PARTICIPANTS 818 patients aged≤45 years at 51 Spanish centers with CKDUE, and either an estimated glomerular filtration rate of<15mL/min/1.73m2 or treatment with maintenance dialysis or transplantation. OBSERVATIONS Genetic testing for 529 genes associated with inherited nephropathies using high-throughput sequencing (HTS). Pathogenic and/or likely pathogenic (P/LP) gene variants concordant with the inheritance pattern were detected in 203 patients (24.8%). Variants in type IV collagen genes were the most frequent (COL4A5, COL4A4, COL4A3; 35% of total gene variants), followed by NPHP1, PAX2, UMOD, MUC1, and INF2 (7.3%, 5.9%, 2.5%, 2.5%, and 2.5%, respectively). Overall, 87 novel variants classified as P/LP were identified. The top 5 most common previously undiagnosed diseases were Alport syndrome spectrum (35% of total positive reports), genetic podocytopathies (19%), nephronophthisis (11%), autosomal dominant tubulointerstitial kidney disease (7%), and congenital anomalies of the kidney and urinary tract (CAKUT, 5%). A family history of kidney disease was reported by 191 participants (23.3%) and by 65 of 203 patients (32.0%) with P/LP variants. LIMITATIONS Missing data, and selection bias resulting from voluntary enrollment. CONCLUSIONS Genomic testing with HTS identified a genetic cause of kidney disease in approximately one quarter of young patients with CKDUE and advanced kidney disease. These findings suggest that genetic studies are a potentially useful tool for the evaluation of people with CKDUE. PLAIN-LANGUAGE SUMMARY The cause of kidney disease is unknown for 1 in 5 patients requiring kidney replacement therapy, reflecting possible prior missed treatment opportunities. We assessed the diagnostic utility of genetic testing in children and adults aged≤45 years with either an estimated glomerular filtration rate of<15mL/min/1.73m2 or treatment with maintenance dialysis or transplantation. Genetic testing identified the cause of kidney disease in approximately 1 in 4 patients without a previously known cause of kidney disease, suggesting that genetic studies are a potentially useful tool for the evaluation of these patients.
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Affiliation(s)
- Miquel Blasco
- Nephrology and Kidney Transplant Department, National Reference Center for Complex Glomerular Diseases, Hospital Clínic, Barcelona University, Barcelona; Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona; RICORS2040, Universidad Autónoma de Madrid, Madrid
| | - Borja Quiroga
- IIS-La Princesa, Servicio de Nefrología, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Madrid; RICORS2040, Universidad Autónoma de Madrid, Madrid
| | - José M García-Aznar
- Clinical Area of Genetic Diagnostic in Nephrology and Immunology, Health in Code, A Coruña
| | - Cristina Castro-Alonso
- Department of Nephrology, Doctor Peset University Hospital, Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunitat Valenciana, Valencia
| | - Saulo J Fernández-Granados
- Hospital Universitario Insular de Gran Canaria, Nephrology Service, Las Palmas de Gran Canaria, Las Palmas
| | - Enrique Luna
- Complejo Hospitalario Universitario de Badajoz, Unidad Enfermedades Genéticas Renales, Servicio de Nefrologia, Badajoz
| | - Gema Fernández Fresnedo
- Nephrology Department, Hospital Marqués de Valdecilla-Grupo de Inmunopatología IDIVAL, Santander
| | - Marta Ossorio
- Nephrology Department, Hospital Universitario La Paz, Universidad Autónoma de Madrid, Madrid
| | | | | | | | - Ricardo Mouzo
- Nephrology Department, Hospital El Bierzo, Ponferrada, Spain
| | - Mercedes Cao
- Nephrology Department, Complexo Hospitalario Universitario A Coruña, A Coruña
| | | | | | - Roser Torra
- Inherited Kidney Diseases, Nephrology Department, Fundació Puigvert, Institut de Recerca Sant Pau, Medicine Department, Universitat Autònoma de Barcelona, Barcelona; RICORS2040, Universidad Autónoma de Madrid, Madrid
| | - Alberto Ortiz
- RICORS2040, Universidad Autónoma de Madrid, Madrid; Nephrology and Hypertension Department, IIS-Fundación Jiménez Díaz, Universidad Autónoma de Madrid, Madrid; Medicine Department, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid.
| | - Patricia de Sequera
- Nephrology Department, Hospital Universitario Infanta Leonor, Universidad Autónoma de Madrid, Madrid; RICORS2040, Universidad Autónoma de Madrid, Madrid; Universidad Complutense de Madrid, Universidad Autónoma de Madrid, Madrid.
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Savige J. Tips for Testing Adults With Suspected Genetic Kidney Disease. Am J Kidney Dis 2024; 83:816-824. [PMID: 38147894 DOI: 10.1053/j.ajkd.2023.10.011] [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: 04/10/2023] [Revised: 10/08/2023] [Accepted: 10/14/2023] [Indexed: 12/28/2023]
Abstract
Genetic kidney disease is common but often unrecognized. It accounts for most cystic kidney diseases and tubulopathies, many forms of congenital abnormalities of the kidney and urinary tract (CAKUT), and some glomerulopathies. Genetic kidney disease is typically suspected where the disease usually has a genetic basis or there is another affected family member, a young age at onset, or extrarenal involvement, but there are also many exceptions to these "rules". Genetic testing requires the patient's written informed consent. When a patient declines testing, another later conversation may be worthwhile. Genetic testing not only indicates the diagnosis but also the inheritance pattern, likely at-risk family members, disease in other organs, clinical course, and possibly effective treatments. Sometimes genetic testing does not identify a pathogenic variant even where other evidence is strong. A variant of uncertain significance (VUS) may be reported but should not be used for clinical decision making. It may be reclassified after more information becomes available without necessarily retesting the patient. Patients should be provided with a copy of their genetic test report, the results explained, and at-risk family members offered "cascade" testing. A referral to a clinical geneticist or genetic counselor helps identify affected family members and in providing advice to assist with reproductive decisions.
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Affiliation(s)
- Judy Savige
- University of Melbourne Department of Medicine (Melbourne Health and Northern health), Royal Melbourne Hospital, Parkville, Australia.
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Zhao Y, Zheng Q, Xie J. Exploration of Gene Therapy for Alport Syndrome. Biomedicines 2024; 12:1159. [PMID: 38927366 PMCID: PMC11200676 DOI: 10.3390/biomedicines12061159] [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: 03/31/2024] [Revised: 05/04/2024] [Accepted: 05/14/2024] [Indexed: 06/28/2024] Open
Abstract
Alport syndrome is a hereditary disease caused by mutations in the genes encoding the alpha 3, alpha 4, and alpha 5 chains of type IV collagen. It is characterized by hematuria, proteinuria, progressive renal dysfunction, hearing loss, and ocular abnormalities. The main network of type IV collagen in the glomerular basement membrane is composed of α3α4α5 heterotrimer. Mutations in these genes can lead to the replacement of this network by an immature network composed of the α1α1α2 heterotrimer. Unfortunately, this immature network is unable to provide normal physical support, resulting in hematuria, proteinuria, and progressive renal dysfunction. Current treatment options for Alport syndrome include angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, which aim to alleviate glomerular filtration pressure, reduce renal injury, and delay the progression of renal dysfunction. However, the effectiveness of these treatments is limited, highlighting the need for novel therapeutic strategies and medications to improve patient outcomes. Gene therapy, which involves the use of genetic material to prevent or treat diseases, holds promise for the treatment of Alport syndrome. This approach may involve the insertion or deletion of whole genes or gene fragments to restore or disrupt gene function or the editing of endogenous genes to correct genetic mutations and restore functional protein synthesis. Recombinant adeno-associated virus (rAAV) vectors have shown significant progress in kidney gene therapy, with several gene therapy drugs based on these vectors reaching clinical application. Despite the challenges posed by the structural characteristics of the kidney, the development of kidney gene therapy using rAAV vectors is making continuous progress. This article provides a review of the current achievements in gene therapy for Alport syndrome and discusses future research directions in this field.
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Affiliation(s)
- Yafei Zhao
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; (Y.Z.); (Q.Z.)
- Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Qimin Zheng
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; (Y.Z.); (Q.Z.)
- Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jingyuan Xie
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China; (Y.Z.); (Q.Z.)
- Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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Yu S, Gu X, Zheng Q, Liu Y, Suhas T, Du W, Xie L, Fang Z, Zhao Y, Yang M, Xu J, Wang Y, Lin MH, Pan X, Miner JH, Jin Y, Xie J. Tauroursodeoxycholic acid ameliorates renal injury induced by COL4A3 mutation. Kidney Int 2024:S0085-2538(24)00334-X. [PMID: 38782199 DOI: 10.1016/j.kint.2024.04.015] [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: 09/09/2023] [Revised: 03/17/2024] [Accepted: 04/25/2024] [Indexed: 05/25/2024]
Abstract
COL4A3/A4/A5 mutations have been identified as critical causes of Alport syndrome and other genetic chronic kidney diseases. However, the underlying pathogenesis remains unclear, and specific treatments are lacking. Here, we constructed a transgenic Alport syndrome mouse model by generating a mutation (Col4a3 p.G799R) identified previously from one large Alport syndrome family into mice. We observed that the mutation caused a pathological decrease in intracellular and secreted collagen IV α3α4α5 heterotrimers. The mutant collagen IV α3 chains abnormally accumulated in the endoplasmic reticulum and exhibited defective secretion, leading to persistent endoplasmic reticulum stress in vivo and in vitro. RNA-seq analysis revealed that the MyD88/p38 MAPK pathway plays key roles in mediating subsequent inflammation and apoptosis signaling activation. Treatment with tauroursodeoxycholic acid, a chemical chaperone drug that functions as an endoplasmic reticulum stress inhibitor, effectively suppressed endoplasmic reticulum stress, promoted secretion of the α3 chains, and inhibited the activation of the MyD88/p38 MAPK pathway. Tauroursodeoxycholic acid treatment significantly improved kidney function in vivo. These results partly clarified the pathogenesis of kidney injuries associated with Alport syndrome, especially in glomeruli, and suggested that tauroursodeoxycholic acid might be useful for the early clinical treatment of Alport syndrome.
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Affiliation(s)
- Shuwen Yu
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiangchen Gu
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Nephrology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Qimin Zheng
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yunzi Liu
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Teija Suhas
- Division of Nephrology, Department of Medicine and Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Wen Du
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lin Xie
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhengying Fang
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yafei Zhao
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Mingxin Yang
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jing Xu
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yimei Wang
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Meei-Hua Lin
- Division of Nephrology, Department of Medicine and Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Xiaoxia Pan
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jeffrey H Miner
- Division of Nephrology, Department of Medicine and Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Yuanmeng Jin
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Jingyuan Xie
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Mabillard H, Ryan R, Tzoumas N, Gear S, Sayer JA. Explaining Alport syndrome-lessons from the adult nephrology clinic. JOURNAL OF RARE DISEASES (BERLIN, GERMANY) 2024; 3:14. [PMID: 38745975 PMCID: PMC11088994 DOI: 10.1007/s44162-024-00036-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 02/15/2024] [Indexed: 05/16/2024]
Abstract
Alport syndrome is a genetic kidney disease that causes worsening of kidney function over time, often progressing to kidney failure. Some types of Alport syndrome cause other symptoms and signs, including hearing loss and eye abnormalities. Research now indicates that Alport syndrome (autosomal dominant inheritance) is the most common form. Alport syndrome can have X-linked or a rare form of autosomal recessive inheritance. Traditionally, a kidney biopsy was used to diagnose Alport syndrome, but genetic testing provides a more precise and less invasive means of diagnosis and reveals the underlying pattern of inheritance. At present, there are no specific curative treatments for Alport syndrome however there is a strong international effort in pursuit of future therapies. Currently, angiotensin-converting enzyme inhibitors (ACEi), or an angiotensin receptor blocker (ARB) if a patient cannot tolerate an ACEi, slow down the progression of kidney disease and can delay the onset of kidney failure by years. There are other potential treatments in research that potentially can help delay the onset of kidney issues. Early treatment of patients and identification of their at-risk relatives is a priority. People living with Alport syndrome and their doctors now benefit from an active international research community working on translating further treatments into clinical practice and providing up-to-date clinical guidelines.
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Affiliation(s)
- Holly Mabillard
- Renal Services, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Central Parkway, Newcastle Upon Tyne, UK
| | - Rebecca Ryan
- Renal Services, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
| | - Nik Tzoumas
- Faculty of Medical Sciences, Biosciences Institute, Newcastle University, Central Parkway, Newcastle Upon Tyne, UK
- Sunderland Eye Infirmary, Sunderland, UK
| | - Susie Gear
- Alport UK, Cirencester, Gloucestershire, UK
| | - John A. Sayer
- Renal Services, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Central Parkway, Newcastle Upon Tyne, UK
- NIHR Newcastle Biomedical Research Centre, Newcastle Upon Tyne, UK
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10
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Graziani L, Minotti C, Carriero ML, Bengala M, Lai S, Terracciano A, Novelli A, Novelli G. A Novel COL4A5 Pathogenic Variant Joins the Dots in a Family with a Synchronous Diagnosis of Alport Syndrome and Polycystic Kidney Disease. Genes (Basel) 2024; 15:597. [PMID: 38790225 PMCID: PMC11121527 DOI: 10.3390/genes15050597] [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: 03/29/2024] [Revised: 04/30/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
Alport Syndrome (AS) is the most common genetic glomerular disease, and it is caused by COL4A3, COL4A4, and COL4A5 pathogenic variants. The classic phenotypic spectrum associated with AS ranges from isolated hematuria to chronic kidney disease (CKD) with extrarenal abnormalities. Atypical presentation of the disorder is possible, and it can mislead the diagnosis. Polycystic kidney disease (PKD), which is most frequently associated with Autosomal Dominant PKD (ADPKD) due to PKD1 and PKD2 heterozygous variants, is emerging as a possible clinical manifestation in COL4A3-A5 patients. We describe a COL4A5 novel familial frameshift variant (NM_000495.5: c.1095dup p.(Leu366ValfsTer45)), which was associated with AS and PKD in the hemizygous proband, as well as with PKD, IgA glomerulonephritis and focal segmental glomerulosclerosis (FSGS) in the heterozygous mother. Establishing the diagnosis of AS can sometimes be difficult, especially in the context of misleading family history and atypical phenotypic features. This case study supports the emerging genotypic and phenotypic heterogeneity in COL4A3-A5-associated disorders, as well as the recently described association between PKD and collagen type IV (Col4) defects. We highlight the importance of the accurate phenotyping of all family members and the relevance of next-generation sequencing in the differential diagnosis of hereditary kidney disease.
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Affiliation(s)
- Ludovico Graziani
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, 00133 Rome, Italy; (C.M.); (M.L.C.); (G.N.)
| | - Chiara Minotti
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, 00133 Rome, Italy; (C.M.); (M.L.C.); (G.N.)
| | - Miriam Lucia Carriero
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, 00133 Rome, Italy; (C.M.); (M.L.C.); (G.N.)
| | - Mario Bengala
- Medical Genetics Unit, Tor Vergata University Hospital, 00133 Rome, Italy;
| | - Silvia Lai
- Division of Nephrology, Department of Translational and Precision Medicine, “Sapienza” University, 00133 Rome, Italy;
| | - Alessandra Terracciano
- Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (A.T.); (A.N.)
| | - Antonio Novelli
- Translational Cytogenomics Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (A.T.); (A.N.)
| | - Giuseppe Novelli
- Department of Biomedicine and Prevention, University of Rome “Tor Vergata”, 00133 Rome, Italy; (C.M.); (M.L.C.); (G.N.)
- Medical Genetics Unit, Tor Vergata University Hospital, 00133 Rome, Italy;
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11
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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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12
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Gosselink ME, Snoek R, Cerkauskaite-Kerpauskiene A, van Bakel SPJ, Vollenberg R, Groen H, Cerkauskiene R, Miglinas M, Attini R, Tory K, Claes KJ, van Calsteren K, Servais A, de Jong MFC, Gillion V, Vogt L, Mastrangelo A, Furlano M, Torra R, Bramham K, Wiles K, Ralston ER, Hall M, Liu L, Hladunewich MA, Lely AT, van Eerde AM. Reassuring pregnancy outcomes in women with mild COL4A3-5-related disease (Alport syndrome) and genetic type of disease can aid personalized counseling. Kidney Int 2024; 105:1088-1099. [PMID: 38382843 DOI: 10.1016/j.kint.2024.01.034] [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: 02/25/2023] [Revised: 12/22/2023] [Accepted: 01/08/2024] [Indexed: 02/23/2024]
Abstract
Individualized pre-pregnancy counseling and antenatal care for women with chronic kidney disease (CKD) require disease-specific data. Here, we investigated pregnancy outcomes and long-term kidney function in women with COL4A3-5 related disease (Alport Syndrome, (AS)) in a large multicenter cohort. The ALPART-network (mAternaL and fetal PregnAncy outcomes of women with AlpoRT syndrome), an international collaboration of 17 centers, retrospectively investigated COL4A3-5 related disease pregnancies after the 20th week. Outcomes were stratified per inheritance pattern (X-Linked AS (XLAS)), Autosomal Dominant AS (ADAS), or Autosomal Recessive AS (ARAS)). The influence of pregnancy on estimated glomerular filtration rate (eGFR)-slope was assessed in 192 pregnancies encompassing 116 women (121 with XLAS, 47 with ADAS, and 12 with ARAS). Median eGFR pre-pregnancy was over 90ml/min/1.73m2. Neonatal outcomes were favorable: 100% live births, median gestational age 39.0 weeks and mean birth weight 3135 grams. Gestational hypertension occurred during 23% of pregnancies (reference: 'general' CKD G1-G2 pregnancies incidence is 4-20%) and preeclampsia in 20%. The mean eGFR declined after pregnancy but remained within normal range (over 90ml/min/1.73m2). Pregnancy did not significantly affect eGFR-slope (pre-pregnancy β=-1.030, post-pregnancy β=-1.349). ARAS-pregnancies demonstrated less favorable outcomes (early preterm birth incidence 3/11 (27%)). ARAS was a significant independent predictor for lower birth weight and shorter duration of pregnancy, next to the classic predictors (pre-pregnancy kidney function, proteinuria, and chronic hypertension) though missing proteinuria values and the small ARAS-sample hindered analysis. This is the largest study to date on AS and pregnancy with reassuring results for mild AS, though inheritance patterns could be considered in counseling next to classic risk factors. Thus, our findings support personalized reproductive care and highlight the importance of investigating kidney disease-specific pregnancy outcomes.
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Affiliation(s)
- Margriet E Gosselink
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands; Department of Obstetrics, University Medical Center Utrecht, Utrecht, the Netherlands.
| | - Rozemarijn Snoek
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands; Department of Obstetrics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Agne Cerkauskaite-Kerpauskiene
- Clinic of Gastroenterology, Nephro-Urology and Surgery, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Sophie P J van Bakel
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands; Department of Obstetrics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Renee Vollenberg
- Department of Genetics, University Medical Center Utrecht, Utrecht, the Netherlands; Department of Obstetrics, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Henk Groen
- Department of Epidemiology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Rimante Cerkauskiene
- Clinic of Children's Diseases, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Marius Miglinas
- Clinic of Gastroenterology, Nephro-Urology and Surgery, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Rossella Attini
- Department of Obstetrics and Gynecology SC2U, Città della Salute e della Scienza, Sant'Anna Hospital, Turin, Italy
| | - Kálmán Tory
- MTA-SE Lendulet Nephrogenetic Laboratory, Pediatric Center, Semmelweis University, Budapest, Hungary
| | - Kathleen J Claes
- Department of Nephrology, University Hospital Leuven, Leuven, Belgium
| | - Kristel van Calsteren
- Department of Obstetrics and Gynaecology, University Hospital Leuven, Leuven, Belgium
| | - Aude Servais
- Department of Nephrology and Transplantation, Necker Enfants Maladies University Hospital, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Margriet F C de Jong
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, Groningen, the Netherlands
| | - Valentine Gillion
- Department of Nephrology, Cliniques Universitaires Saint-Luc (Université Catholique de Louvain), Brussels, Belgium
| | - Liffert Vogt
- Section Nephrology, Department of Internal Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| | - Antonio Mastrangelo
- Pediatric Nephrology, Dialysis, and Transplant Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Monica Furlano
- Department of Nephrology, Inherited Kidney Diseases, Fundació Puigvert, Institut d'Investigacions Biomèdiques Sant Pau Universitat Autònoma de Barcelona, RICORS2040 (Kidney Disease), Barcelona, Spain
| | - Roser Torra
- Department of Nephrology, Inherited Kidney Diseases, Fundació Puigvert, Institut d'Investigacions Biomèdiques Sant Pau Universitat Autònoma de Barcelona, RICORS2040 (Kidney Disease), Barcelona, Spain
| | - Kate Bramham
- Department of Women and Children's Health, King's College London, London, UK
| | - Kate Wiles
- Department of Women and Children, Barts National Health Service Trust and Queen Mary University of London, London, UK
| | - Elizabeth R Ralston
- Department of Women and Children's Health, King's College London, London, UK
| | - Matthew Hall
- Department of Nephrology, Nottingham University Hospitals, Nottingham, UK
| | - Lisa Liu
- Division of Nephrology, Department of Medicine, Sunnybrook Health Sciences Centre, Temerty Faculty of Medicine, Toronto, Ontario, Canada
| | - Michelle A Hladunewich
- Division of Nephrology, Department of Medicine, Sunnybrook Health Sciences Centre, Temerty Faculty of Medicine, Toronto, Ontario, Canada
| | - A Titia Lely
- Department of Obstetrics, University Medical Center Utrecht, Utrecht, the Netherlands
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13
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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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14
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Salehi O, Mack H, Colville D, Lewis D, Savige J. Ocular manifestations of renal ciliopathies. Pediatr Nephrol 2024; 39:1327-1346. [PMID: 37644229 PMCID: PMC10942941 DOI: 10.1007/s00467-023-06096-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 07/09/2023] [Accepted: 07/10/2023] [Indexed: 08/31/2023]
Abstract
Renal ciliopathies are a common cause of kidney failure in children and adults, and this study reviewed their ocular associations. Genes affected in renal ciliopathies were identified from the Genomics England Panels. Ocular associations were identified from Medline and OMIM, and the genes additionally examined for expression in the human retina ( https://www.proteinatlas.org/humanproteome/tissue ) and for an ocular phenotype in mouse models ( http://www.informatics.jax.org/ ). Eighty-two of the 86 pediatric-onset renal ciliopathies (95%) have an ocular phenotype, including inherited retinal degeneration, oculomotor disorders, and coloboma. Diseases associated with pathogenic variants in ANK6, MAPKBP1, NEK8, and TCTN1 have no reported ocular manifestations, as well as low retinal expression and no ocular features in mouse models. Ocular abnormalities are not associated with the most common adult-onset "cystic" kidney diseases, namely, autosomal dominant (AD) polycystic kidney disease and the AD tubulointerstitial kidney diseases (ADTKD). However, other kidney syndromes with cysts have ocular features including papillorenal syndrome (optic disc dysplasia), Hereditary Angiopathy Nephropathy, Aneurysms and muscle Cramps (HANAC) (tortuous retinal vessels), tuberous sclerosis (retinal hamartomas), von Hippel-Lindau syndrome (retinal hemangiomas), and Alport syndrome (lenticonus, fleck retinopathy). Ocular abnormalities are associated with many pediatric-onset renal ciliopathies but are uncommon in adult-onset cystic kidney disease. However the demonstration of ocular manifestations may be helpful diagnostically and the features may require monitoring or treatment.
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Affiliation(s)
- Omar Salehi
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Royal Melbourne Hospital, Parkville, VIC, 3050, Australia
| | - Heather Mack
- University Department of Surgery (Ophthalmology), Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, 3002, Australia
| | - Deb Colville
- University Department of Surgery (Ophthalmology), Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, 3002, Australia
| | - Debbie Lewis
- Nephrology Department, The Children's Hospital at Westmead, Westmead, NSW, 2145, Australia
| | - Judy Savige
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Royal Melbourne Hospital, Parkville, VIC, 3050, Australia.
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15
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Puapatanakul P, Miner JH. Alport syndrome and Alport kidney diseases - elucidating the disease spectrum. Curr Opin Nephrol Hypertens 2024; 33:283-290. [PMID: 38477333 PMCID: PMC10990029 DOI: 10.1097/mnh.0000000000000983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2024]
Abstract
PURPOSE OF REVIEW With the latest classification, variants in three collagen IV genes, COL4A3 , COL4A4 , and COL4A5 , represent the most prevalent genetic kidney disease in humans, exhibiting diverse, complex, and inconsistent clinical manifestations. This review breaks down the disease spectrum and genotype-phenotype correlations of kidney diseases linked to genetic variants in these genes and distinguishes "classic" Alport syndrome (AS) from the less severe nonsyndromic genetically related nephropathies that we suggest be called "Alport kidney diseases". RECENT FINDINGS Several research studies have focused on the genotype-phenotype correlation under the latest classification scheme of AS. The historic diagnoses of "benign familial hematuria" and "thin basement membrane nephropathy" linked to heterozygous variants in COL4A3 or COL4A4 are suggested to be obsolete, but instead classified as autosomal AS by recent expert consensus due to a significant risk of disease progression. SUMMARY The concept of Alport kidney disease extends beyond classic AS. Patients carrying pathogenic variants in any one of the COL4A3/A4/A5 genes can have variable phenotypes ranging from completely normal/clinically unrecognizable, hematuria without or with proteinuria, or progression to chronic kidney disease and kidney failure, depending on sex, genotype, and interplays of other genetic as well as environmental factors.
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Affiliation(s)
- Pongpratch Puapatanakul
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Nephrology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Jeffrey H. Miner
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
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16
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Greenberg D, Rosenblum ND, Tonelli M. The multifaceted links between hearing loss and chronic kidney disease. Nat Rev Nephrol 2024; 20:295-312. [PMID: 38287134 DOI: 10.1038/s41581-024-00808-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2024] [Indexed: 01/31/2024]
Abstract
Hearing loss affects nearly 1.6 billion people and is the third-leading cause of disability worldwide. Chronic kidney disease (CKD) is also a common condition that is associated with adverse clinical outcomes and high health-care costs. From a developmental perspective, the structures responsible for hearing have a common morphogenetic origin with the kidney, and genetic abnormalities that cause familial forms of hearing loss can also lead to kidney disease. On a cellular level, normal kidney and cochlea function both depend on cilial activities at the apical surface, and kidney tubular cells and sensory epithelial cells of the inner ear use similar transport mechanisms to modify luminal fluid. The two organs also share the same collagen IV basement membrane network. Thus, strong developmental and physiological links exist between hearing and kidney function. These theoretical considerations are supported by epidemiological data demonstrating that CKD is associated with a graded and independent excess risk of sensorineural hearing loss. In addition to developmental and physiological links between kidney and cochlear function, hearing loss in patients with CKD may be driven by specific medications or treatments, including haemodialysis. The associations between these two common conditions are not commonly appreciated, yet have important implications for research and clinical practice.
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Affiliation(s)
- Dina Greenberg
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, Toronto, Ontario, Canada
| | - Norman D Rosenblum
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, Toronto, Ontario, Canada
- Department of Paediatrics, Temerty Faculty of Medicine, Toronto, Ontario, Canada
| | - Marcello Tonelli
- Department of Medicine, University of Calgary, Calgary, Alberta, Canada.
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17
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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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18
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Zheng Q, Gu X, He JC, Xie J. Progress in therapeutic targets on podocyte for Alport syndrome. J Transl Int Med 2024; 12:129-133. [PMID: 38812923 PMCID: PMC11135632 DOI: 10.2478/jtim-2024-0005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024] Open
Affiliation(s)
- Qimin Zheng
- Department of Nephrology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
- Institute of Nephrology, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Xiangchen Gu
- Department of Nephrology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
- Institute of Nephrology, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - John Cijiang He
- Department of Medicine, Barbara T. Murphy Division of Nephrology, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Jingyuan Xie
- Department of Nephrology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
- Institute of Nephrology, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
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19
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Riedhammer KM, Simmendinger H, Tasic V, Putnik J, Abazi-Emini N, Stajic N, Berutti R, Weidenbusch M, Patzer L, Lungu A, Milosevski-Lomic G, Günthner R, Braunisch MC, Ćomić J, Hoefele J. Is there a dominant-negative effect in individuals with heterozygous disease-causing variants in COL4A3/COL4A4? Clin Genet 2024; 105:406-414. [PMID: 38214412 DOI: 10.1111/cge.14471] [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: 10/29/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 01/13/2024]
Abstract
Alport syndrome (AS) shows a broad phenotypic spectrum ranging from isolated microscopic hematuria (MH) to end-stage kidney disease (ESKD). Monoallelic disease-causing variants in COL4A3/COL4A4 have been associated with autosomal dominant AS (ADAS) and biallelic variants with autosomal recessive AS (ARAS). The aim of this study was to analyze clinical and genetic data regarding a possible genotype-phenotype correlation in individuals with disease-causing variants in COL4A3/COL4A4. Eighty-nine individuals carrying at least one COL4A3/COL4A4 variant classified as (likely) pathogenic according to the American College of Medical Genetics guidelines and current amendments were recruited. Clinical data concerning the prevalence and age of first reported manifestation of MH, proteinuria, ESKD, and extrarenal manifestations were collected. Individuals with monoallelic non-truncating variants reported a significantly higher prevalence and earlier diagnosis of MH and proteinuria than individuals with monoallelic truncating variants. Individuals with biallelic variants were more severely affected than those with monoallelic variants. Those with biallelic truncating variants were more severely affected than those with compound heterozygous non-truncating/truncating variants or individuals with biallelic non-truncating variants. In this study an association of heterozygous non-truncating COL4A3/COL4A4 variants with a more severe phenotype in comparison to truncating variants could be shown indicating a potential dominant-negative effect as an explanation for this observation. The results for individuals with ARAS support the, still scarce, data in the literature.
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Affiliation(s)
- Korbinian M Riedhammer
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, TUM School of Medicine and Health, Munich, Germany
- Department of Nephrology, Klinikum rechts der Isar, Technical University of Munich, TUM School of Medicine and Health, Munich, Germany
| | - Hannes Simmendinger
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, TUM School of Medicine and Health, Munich, Germany
| | - Velibor Tasic
- Medical Faculty of Skopje, University Children's Hospital, Macedonia
| | - Jovana Putnik
- Institute for Mother and Child Health Care of Serbia "Dr Vukan Čupić", Department of Nephrology, University of Belgrade, Faculty of Medicine, Belgrade, Serbia
| | - Nora Abazi-Emini
- Medical Faculty of Skopje, University Children's Hospital, Macedonia
| | - Natasa Stajic
- Institute for Mother and Child Health Care of Serbia "Dr Vukan Čupić", Department of Nephrology, University of Belgrade, Faculty of Medicine, Belgrade, Serbia
| | - Riccardo Berutti
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, TUM School of Medicine and Health, Munich, Germany
| | - Marc Weidenbusch
- Nephrologisches Zentrum, Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Ludwig-Maximilians University, Munich, Germany
| | - Ludwig Patzer
- Department of Pediatric Nephrology, Children's Hospital St. Elisabeth and St. Barbara, Halle/Saale, Germany
| | - Adrian Lungu
- Pediatric Nephrology Department, Fundeni Clinical Institute, Bucharest, Romania
| | - Gordana Milosevski-Lomic
- Institute for Mother and Child Health Care of Serbia "Dr Vukan Čupić", Department of Nephrology, University of Belgrade, Faculty of Medicine, Belgrade, Serbia
| | - Roman Günthner
- Department of Nephrology, Klinikum rechts der Isar, Technical University of Munich, TUM School of Medicine and Health, Munich, Germany
| | - Matthias C Braunisch
- Department of Nephrology, Klinikum rechts der Isar, Technical University of Munich, TUM School of Medicine and Health, Munich, Germany
| | - Jasmina Ćomić
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, TUM School of Medicine and Health, Munich, Germany
- Department of Nephrology, Klinikum rechts der Isar, Technical University of Munich, TUM School of Medicine and Health, Munich, Germany
| | - Julia Hoefele
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, TUM School of Medicine and Health, Munich, Germany
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20
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Zeni L, Mescia F, Toso D, Dordoni C, Mazza C, Savoldi G, Econimo L, Cortinovis R, Fisogni S, Alberici F, Scolari F, Izzi C. Clinical Significance of the Cystic Phenotype in Alport Syndrome. Am J Kidney Dis 2024:S0272-6386(24)00681-4. [PMID: 38514012 DOI: 10.1053/j.ajkd.2024.02.005] [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: 09/21/2023] [Revised: 01/16/2024] [Accepted: 02/02/2024] [Indexed: 03/23/2024]
Abstract
RATIONALE & OBJECTIVE Alport syndrome (AS) is the most common genetic glomerular disease caused by mutations that affect type IV collagen. However, the clinical characteristics and significance of AS with kidney cysts are not well defined. This study investigated the prevalence and clinical significance of cystic kidney phenotype in AS. STUDY DESIGN Retrospective cohort study. SETTING & PARTICIPANTS One hundred-eight patients with AS and a comparison cohort of 79 patients with IgA nephropathy (IgAN). Clinical, genetic, and imaging data were collected from medical records. EXPOSURE Cystic kidney phenotype evaluated by ultrasonography and defined as the presence of≥3 cysts in each kidney; demographic characteristics and estimated glomerular filtration rate (eGFR) at disease onset. OUTCOME Cystic kidney phenotype in the AS and IgAN cohorts; time to chronic kidney disease (CKD) stage 3b and longitudinal changes in eGFR in the AS cohort. ANALYTICAL APPROACH Logistic regression analysis to test independent strengths of associations of clinical/demographic features with the binary outcome of cystic phenotype. Survival analysis for the outcome of reaching CKD stage 3b and linear mixed models for changes in eGFR over time in the AS cohort. RESULTS We studied 108 patients with AS; 76 (70%) had a genetic diagnosis. Autosomal dominant AS was prevalent, accounting for 68% of patients with a genetic diagnosis. Cystic kidney phenotype was observed in 38% of patients with AS and was associated with normal-sized kidneys in all but 3 patients, who showed increased total kidney volume, mimicking autosomal dominant polycystic kidney disease. The prevalence of cystic kidney phenotype was significantly higher in patients with AS when compared with the group of patients with IgAN (42% vs 19%; P=0.002). Patients with the cystic kidney phenotype were older and had more marked reduction in eGFR than patients without cystic changes. Among patients with AS, the cystic phenotype was associated with older age and a faster decline eGFR. LIMITATIONS Retrospective, single-center study. CONCLUSIONS Cystic kidney phenotype is a common finding in AS. The cystic kidney phenotype is a common finding in AS, suggesting a possible role in cystogenesis for the genetic variants that cause this disease. PLAIN-LANGUAGE SUMMARY Hematuria is the classic renal presentation of Alport syndrome (AS), a hereditary glomerulopathy caused by pathogenic variants of the COL4A3-5 genes. An atypical kidney cystic phenotype has been rarely reported in individuals with these variants. To determine the prevalence of kidney cysts, we performed abdominal ultrasonography in a large group of patients with AS and a comparison group of patients with another glomerular kidney disease, IgA nephropathy (IgAN). Multiple kidney cysts, usually with normal kidney volume, were found in 38% of patients with AS. A few patients' kidney volumes were large enough to mimic a different hereditary cystic kidney disease, autosomal dominant polycystic kidney disease. The overall prevalence of kidney cysts in AS was more than double that observed in the well-matched comparison group with IgAN. These findings emphasize the high prevalence of cystic kidney phenotype in AS, suggesting a likely association between the genetic variants that cause this disease and the development of kidney cysts.
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Affiliation(s)
- Letizia Zeni
- Division of Nephrology and Dialysis, Azienda Socio Sanitaria Territoriale (ASST) Spedali Civili
| | - Federica Mescia
- Division of Nephrology and Dialysis, Azienda Socio Sanitaria Territoriale (ASST) Spedali Civili; Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
| | - Diego Toso
- Division of Nephrology and Dialysis, Azienda Socio Sanitaria Territoriale (ASST) Spedali Civili; Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
| | - Chiara Dordoni
- Clinical Genetics Unit, Department of Obstetrics and Gynaecology, Azienda Socio Sanitaria Territoriale (ASST) Spedali Civili
| | - Cinzia Mazza
- Medical Genetics Laboratory, Azienda Socio Sanitaria Territoriale (ASST) Spedali Civili
| | - Gianfranco Savoldi
- Medical Genetics Laboratory, Azienda Socio Sanitaria Territoriale (ASST) Spedali Civili
| | - Laura Econimo
- Division of Nephrology and Dialysis, Azienda Socio Sanitaria Territoriale (ASST) Spedali Civili
| | - Roberta Cortinovis
- Division of Nephrology and Dialysis, Azienda Socio Sanitaria Territoriale (ASST) Spedali Civili
| | - Simona Fisogni
- Section of Pathology, Department of Molecular and Translational Medicine, ASST-Spedali Civili, University of Brescia, Brescia, Italy
| | - Federico Alberici
- Division of Nephrology and Dialysis, Azienda Socio Sanitaria Territoriale (ASST) Spedali Civili; Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
| | - Francesco Scolari
- Division of Nephrology and Dialysis, Azienda Socio Sanitaria Territoriale (ASST) Spedali Civili; Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
| | - Claudia Izzi
- Clinical Genetics Unit, Department of Obstetrics and Gynaecology, Azienda Socio Sanitaria Territoriale (ASST) Spedali Civili; Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy.
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21
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Xiao T, Zhang J, Liu L, Zhang B. Genetic diagnosis of Alport syndrome in 16 Chinese families. Mol Genet Genomic Med 2024; 12:e2406. [PMID: 38433557 PMCID: PMC10910213 DOI: 10.1002/mgg3.2406] [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: 04/21/2023] [Revised: 05/05/2023] [Accepted: 02/07/2024] [Indexed: 03/05/2024] Open
Abstract
BACKGROUND Alport syndrome (AS) is a genetically heterogeneous disorder resulting from mutations in the collagen IV genes COL4A3, COL4A4, and COL4A5. The genetic diagnosis of AS is very important to make precise diagnosis and achieve optimal outcomes. METHODS In this study, 16 Chinese families with suspected AS were recruited after pedigree analysis, and the clinical presentations were analyzed by a nephrologist. The genetic diagnosis was performed by whole-exome sequencing (WES) and the disease-causing variants were confirmed by Sanger sequencing. RESULTS The cohort of probands included seven men and nine women, with a mean age of 19.9 years. Pathological analysis showed slight-to-moderate mesangial proliferation, and thin basement membrane was the main findings. Pathogenic variants were revealed by WES in each family, and the co-segregation with renal presentation was confirmed by PCR. In addition, RT-PCR analysis showed that the intronic variant led to aberrant splicing. CONCLUSION Our findings expand the spectrum of AS gene variation, which will inform genetic diagnosis and add to the theoretical basis for the prevention of AS.
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Affiliation(s)
- Tangli Xiao
- Department of Nephrology, the Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Chongqing Clinical Research Center of Kidney and Urology DiseasesXinqiao Hospital, Army Medical University (Third Military Medical University)ChongqingP.R. China
| | - Jun Zhang
- Department of Nephrology, the Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Chongqing Clinical Research Center of Kidney and Urology DiseasesXinqiao Hospital, Army Medical University (Third Military Medical University)ChongqingP.R. China
| | - Li Liu
- Department of Nephrology, the Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Chongqing Clinical Research Center of Kidney and Urology DiseasesXinqiao Hospital, Army Medical University (Third Military Medical University)ChongqingP.R. China
| | - Bo Zhang
- Department of Nephrology, the Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Chongqing Clinical Research Center of Kidney and Urology DiseasesXinqiao Hospital, Army Medical University (Third Military Medical University)ChongqingP.R. China
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22
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Madison J, Wilhelm K, Meehan DT, Gratton MA, Vosik D, Samuelson G, Ott M, Fascianella J, Nelson N, Cosgrove D. Ramipril therapy in integrin α1-null, autosomal recessive Alport mice triples lifespan: mechanistic clues from RNA-seq analysis. J Pathol 2024; 262:296-309. [PMID: 38129319 PMCID: PMC10872630 DOI: 10.1002/path.6231] [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: 02/09/2023] [Revised: 10/10/2023] [Accepted: 10/29/2023] [Indexed: 12/23/2023]
Abstract
The standard of care for patients with Alport syndrome (AS) is angiotensin-converting enzyme (ACE) inhibitors. In autosomal recessive Alport (ARAS) mice, ACE inhibitors double lifespan. We previously showed that deletion of Itga1 in Alport mice [double-knockout (DKO) mice] increased lifespan by 50%. This effect seemed dependent on the prevention of laminin 211-mediated podocyte injury. Here, we treated DKO mice with vehicle or ramipril starting at 4 weeks of age. Proteinuria and glomerular filtration rates were measured at 5-week intervals. Glomeruli were analyzed for laminin 211 deposition in the glomerular basement membrane (GBM) and GBM ultrastructure was analyzed using transmission electron microscopy (TEM). RNA sequencing (RNA-seq) was performed on isolated glomeruli at all time points and the results were compared with cultured podocytes overlaid (or not) with recombinant laminin 211. Glomerular filtration rate declined in ramipril-treated DKO mice between 30 and 35 weeks. Proteinuria followed these same patterns with normalization of foot process architecture in ramipril-treated DKO mice. RNA-seq revealed a decline in the expression of Foxc2, nephrin (Nphs1), and podocin (Nphs2) mRNAs, which was delayed in the ramipril-treated DKO mice. GBM accumulation of laminin 211 was delayed in ramipril-treated DKO mice, likely due to a role for α1β1 integrin in CDC42 activation in Alport mesangial cells, which is required for mesangial filopodial invasion of the subendothelial spaces of the glomerular capillary loops. Ramipril synergized with Itga1 knockout, tripling lifespan compared with untreated ARAS mice. © 2023 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Jacob Madison
- Boys Town National Research Hospital, Omaha, NE, USA
| | - Kevin Wilhelm
- Boys Town National Research Hospital, Omaha, NE, USA
| | | | | | - Denise Vosik
- Boys Town National Research Hospital, Omaha, NE, USA
| | | | - Megan Ott
- Boys Town National Research Hospital, Omaha, NE, USA
| | | | - Noa Nelson
- Boys Town National Research Hospital, Omaha, NE, USA
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23
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Yavas C, Ozgenturk NO, Dogan M, Gezdirici A, Keskin E, İli EG, Dogan T, Celebi E, Bender O, Un C. A Deeper Insight into COL4A3, COL4A4, and COL4A5 Variants and Genotype-Phenotype Correlation of a Turkish Cohort with Alport Syndrome. Mol Syndromol 2024; 15:1-13. [PMID: 38357258 PMCID: PMC10862325 DOI: 10.1159/000533915] [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: 05/16/2023] [Accepted: 08/26/2023] [Indexed: 02/16/2024] Open
Abstract
Introduction Alport syndrome (AS) is an inherited, rare, progressive kidney disease that affects the eye and ear physiology. Pathogenic variants of COL4A5 account for 85% of all cases, while COL4A3 and COL4A4 account for the remaining 15%. Methods Targeted next-generation sequencing of the COL4A3, COL4A4, and COL4A5 genes was performed in 125 Turkish patients with AS. The patients were compared to 45 controls and open-access population data. Results The incidence of AS variants in patients was found as 21.6%. 27 variants were identified as pathogenic/likely pathogenic, 28 as variant of uncertain significance, and 52 as benign/likely benign. We also found 31 novel variants (14 in COL4A3, 6 in COL4A4, and 11 in COL4A5) of which 27 were classified as pathogenic/likely pathogenic. Pathogenic/likely Pathogenic variants were most commonly found in the COL4A5 gene, consistent with the literature. This study contributed novel variants associated with AS to the literature. Conclusion Genetic testing is a crucial part for the diagnosis and management of AS. Studies on the genetic etiology of AS are limited for the Turkish population. We believe that this study will contribute to the literature and the clinical decision-making process of patients with AS and emphasize the importance of genetic counseling.
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Affiliation(s)
- Cuneyd Yavas
- Department of Medical Genetics, Başaksehir Çam and Sakura City Hospital, Istanbul, Turkey
| | - Nehir Ozdemir Ozgenturk
- Department of Molecular Biology and Genetics, Faculty of Arts and Sciences, Yildiz Technical University, Istanbul, Turkey
| | - Mustafa Dogan
- Department of Medical Genetics, Başaksehir Çam and Sakura City Hospital, Istanbul, Turkey
| | - Alper Gezdirici
- Department of Medical Genetics, Başaksehir Çam and Sakura City Hospital, Istanbul, Turkey
| | - Ece Keskin
- Haseki Training and Research Hospital, Clinic of Medical Genetic, Istanbul, Turkey
| | - Ezgi Gokpınar İli
- Department of Medical Genetics, Başaksehir Çam and Sakura City Hospital, Istanbul, Turkey
| | - Tunay Dogan
- Department of Pathology, Faculty of Medicine, Istinye University, Istanbul, Turkey
| | - Evrim Celebi
- Department of Medical Genetics, Başaksehir Çam and Sakura City Hospital, Istanbul, Turkey
| | - Onur Bender
- Biotechnology Institute, Ankara University, Ankara, Turkey
| | - Cemal Un
- Department of Biology Molecular Biology Section, Ege University Faculty of Science, İzmir, Turkey
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24
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Juan-Juan D, Jia W, Li-Li L, Si W, Xiao-Wen W, Jiang-Wei L, Li-Qin K, Jie S, Pei-Wei Z. Genetic, Clinical, and Pathologic Backgrounds of Children With X-Linked Alport Syndrome in China: A Monocenter Study. Glob Pediatr Health 2024; 11:2333794X231221935. [PMID: 38249544 PMCID: PMC10799596 DOI: 10.1177/2333794x231221935] [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: 07/31/2023] [Accepted: 12/05/2023] [Indexed: 01/23/2024] Open
Abstract
Background. Characteristics of X-linked Alport syndrome (XLAS) in a cohort of Chinese children. Methods. This work is a retrospective study covering the clinical information, pathological data, and gene sequencing results of 32 cases with XLAS from 2011 to 2022. Results. Among these 32 patients, the youngest age of onset was 3 months. Renal biopsy was performed on 29 children. The lamellated glomerular basement membrane was observed in 19 children using electron microscopy (65.5%). Of the 26 samples tested, 73.1% were found to be negative for collagen-a5 under immunohistochemical staining, showing clinical significance. Next-generation sequencing (NGS) detected 27 pathogenic gene mutations. A total of 15.4% of patients carried de novo mutations. Conclusions. The boys with XLAS showed more typical pathological performance than the girls. Patients with severe mutation were more likely to have proteinuria and hearing impairment. Renal pathology combined with NSG is an important means of diagnosis of AS.
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Affiliation(s)
- Ding Juan-Juan
- Wuhan Children’s Hospital (Wuhan Maternal and Child Healthcare Hospital),Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei, China
| | - Wang Jia
- Wuhan Children’s Hospital (Wuhan Maternal and Child Healthcare Hospital),Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei, China
| | - Liu Li-Li
- Wuhan Children’s Hospital (Wuhan Maternal and Child Healthcare Hospital),Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei, China
| | - Wang Si
- Wuhan Children’s Hospital (Wuhan Maternal and Child Healthcare Hospital),Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei, China
| | - Wang Xiao-Wen
- Wuhan Children’s Hospital (Wuhan Maternal and Child Healthcare Hospital),Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei, China
| | - Luan Jiang-Wei
- Wuhan Children’s Hospital (Wuhan Maternal and Child Healthcare Hospital),Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei, China
| | - Ke Li-Qin
- Wuhan Children’s Hospital (Wuhan Maternal and Child Healthcare Hospital),Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei, China
| | - Sun Jie
- Wuhan Children’s Hospital (Wuhan Maternal and Child Healthcare Hospital),Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei, China
| | - Zhao Pei-Wei
- Wuhan Children’s Hospital (Wuhan Maternal and Child Healthcare Hospital),Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei, China
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25
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Torra R, Kronbichler A, Bajema IM. Replacing a kidney biopsy by exome sequencing in undetermined kidney diseases-not yet ready for prime time! Clin Kidney J 2024; 17:sfad250. [PMID: 38186890 PMCID: PMC10768749 DOI: 10.1093/ckj/sfad250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Indexed: 01/09/2024] Open
Affiliation(s)
- Roser Torra
- Inherited Kidney Diseases, Nephrology Department, Fundació Puigvert, Institut d'Investigacions Biomèdiques (IIB-Sant Pau), Department of Medicine, Universitat Autonoma de Barcelona (UAB), Spain
| | - Andreas Kronbichler
- Department of Internal Medicine IV, Nephrology and Hypertension, Medical University Innsbruck, Innsbruck, Austria
| | - Ingeborg M Bajema
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center, Groningen, The Netherlands
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26
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Tkemaladze T, Bregvadze K, Kvaratskhelia E, Abzianidze E, Davitaia T. A founder COL4A3 pathogenic variant resulting in Alport syndrome and thin basement membrane disease: a case report series. Front Med (Lausanne) 2023; 10:1281049. [PMID: 38188341 PMCID: PMC10768050 DOI: 10.3389/fmed.2023.1281049] [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: 08/21/2023] [Accepted: 12/05/2023] [Indexed: 01/09/2024] Open
Abstract
Alport syndrome is a rare genetic condition characterized by kidney disease, hearing impairment, and ocular abnormalities. It exhibits various inheritance patterns involving pathogenic variants in COL4A3, COL4A4, and COL4A5 genes. The phenotypes can range from isolated hematuria with a non-progressive or very slowly progressive course to progressive kidney disease with extrarenal abnormalities. Timely diagnosis of Alport syndrome facilitates the early and effective implementation of treatment, as well as genetic counseling. Here, we report the COL4A3 c.765G > A, p.((=)) mutation in three ethnically Azerbaijani, apparently unrelated, consanguineous families from the village of Algeti in the Marneuli region of Georgia. We speculate that this variant could represent a founder mutation within this population and recommend offering genetic testing to Algeti village residents with persistent hematuria.
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Affiliation(s)
- Tinatin Tkemaladze
- Department of Molecular and Medical Genetics, Tbilisi State Medical University, Tbilisi, Georgia
- Department of Pediatrics, Givi Zhvania Pediatric Academic Clinic, Tbilisi State Medical University, Tbilisi, Georgia
| | - Kakha Bregvadze
- Department of Molecular and Medical Genetics, Tbilisi State Medical University, Tbilisi, Georgia
| | - Eka Kvaratskhelia
- Department of Molecular and Medical Genetics, Tbilisi State Medical University, Tbilisi, Georgia
| | - Elene Abzianidze
- Department of Molecular and Medical Genetics, Tbilisi State Medical University, Tbilisi, Georgia
| | - Tinatin Davitaia
- Department of Pediatrics, Givi Zhvania Pediatric Academic Clinic, Tbilisi State Medical University, Tbilisi, Georgia
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27
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Pokidysheva EN, Redhair N, Ailsworth O, Page-McCaw P, Rollins-Smith L, Jamwal VS, Ohta Y, Bächinger HP, Murawala P, Flajnik M, Fogo AB, Abrahamson D, Hudson JK, Boudko SP, Hudson BG. Collagen IV of basement membranes: II. Emergence of collagen IV α345 enabled the assembly of a compact GBM as an ultrafilter in mammalian kidneys. J Biol Chem 2023; 299:105459. [PMID: 37977222 PMCID: PMC10746531 DOI: 10.1016/j.jbc.2023.105459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/28/2023] [Accepted: 10/31/2023] [Indexed: 11/19/2023] Open
Abstract
The collagen IVα345 (Col-IVα345) scaffold, the major constituent of the glomerular basement membrane (GBM), is a critical component of the kidney glomerular filtration barrier. In Alport syndrome, affecting millions of people worldwide, over two thousand genetic variants occur in the COL4A3, COL4A4, and COL4A5 genes that encode the Col-IVα345 scaffold. Variants cause loss of scaffold, a suprastructure that tethers macromolecules, from the GBM or assembly of a defective scaffold, causing hematuria in nearly all cases, proteinuria, and often progressive kidney failure. How these variants cause proteinuria remains an enigma. In a companion paper, we found that the evolutionary emergence of the COL4A3, COL4A4, COL4A5, and COL4A6 genes coincided with kidney emergence in hagfish and shark and that the COL4A3 and COL4A4 were lost in amphibians. These findings opened an experimental window to gain insights into functionality of the Col-IVα345 scaffold. Here, using tissue staining, biochemical analysis and TEM, we characterized the scaffold chain arrangements and the morphology of the GBM of hagfish, shark, frog, and salamander. We found that α4 and α5 chains in shark GBM and α1 and α5 chains in amphibian GBM are spatially separated. Scaffolds are distinct from one another and from the mammalian Col-IVα345 scaffold, and the GBM morphologies are distinct. Our findings revealed that the evolutionary emergence of the Col-IVα345 scaffold enabled the genesis of a compact GBM that functions as an ultrafilter. Findings shed light on the conundrum, defined decades ago, whether the GBM or slit diaphragm is the primary filter.
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Affiliation(s)
- Elena N Pokidysheva
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Aspirnaut, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
| | - Neve Redhair
- Aspirnaut, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Octavia Ailsworth
- Aspirnaut, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Patrick Page-McCaw
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Louise Rollins-Smith
- Department of Pathology Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | | | - Yuko Ohta
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | | | - Prayag Murawala
- Mount Desert Island Biological Laboratory, Bar Harbor, Maine, USA; Clinic for Kidney and Hypertension Diseases, Hannover Medical School, Hannover, Germany
| | - Martin Flajnik
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Agnes B Fogo
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Dale Abrahamson
- Department of Cell Biology and Physiology, The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Julie K Hudson
- Aspirnaut, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Sergei P Boudko
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Billy G Hudson
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Aspirnaut, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Center for Matrix Biology, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA; Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, USA; Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
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Gao X, Li M, Wang K, Li Z, Han C. Pregnancy in women with autosomal recessive Alport syndrome caused by novel compound heterozygous mutations of COL4A3 gene: Two cases reports. Medicine (Baltimore) 2023; 102:e36057. [PMID: 37986374 PMCID: PMC10659596 DOI: 10.1097/md.0000000000036057] [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: 08/12/2023] [Accepted: 10/20/2023] [Indexed: 11/22/2023] Open
Abstract
RATIONALE Autosomal recessive Alport syndrome (ARAS) is an hereditary heterogeneous disease that poses a serious risk to pregnant women. PATIENT CONCERNS We reported 2 cases of pregnancy with progressive proteinuria. The case 1 was a 21-year-old woman with 24-h proteinuria increased from 2.03 to 11.72 g at 13 to 35 weeks of gestation, and the case 2 was a 28-year-old woman with 24-h proteinuria increased from 2.10 to 9.32 g at 8 to 36 weeks of gestation. In advanced stage of pregnancy, the fetal development was smaller than the gestational age. DIAGNOSES Sanger sequencing showed that novel compound heterozygous mutations [c.1315 G>T (p.G439C) and c.4847 G>A (p.C1616Y)] of the collagen type IV alpha 3 chain (COL4A3) gene were found in the 2 cases. Renal puncture pathology confirmed the diagnosis of ARAS. INTERVENTIONS The 2 cases were treated with albumin, compounded amino acids, calcium, vitamin D, and low molecular weight heparin in addition to conventional treatment during pregnancy. Pregnancy was terminated by cesarean section at 36 to 37 weeks of gestation. After delivery, the patients were treated with Losartan for anti-proteinuric therapy for 1 year. OUTCOMES The neonatal weights and Apgar scores were normal. The patients recovered well and 24-h proteinuria decreased to pre-pregnancy level. LESSONS When pregnant women present with a persistent increasing proteinuria, ARAS needs to be considered. Sanger sequencing is useful to assist in the diagnosis of ARAS. Multidisciplinary treatments from nephrologists and gynecologists are needed to ensure the safety of pregnancy and the fetus.
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Affiliation(s)
- Xiaoli Gao
- Department of Gynecology and Obstetrics, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Key Laboratory of Female Reproductive Health and Eugenics, Tianjin Medical University General Hospital, Tianjin, China
| | - Meilu Li
- Department of Gynecology and Obstetrics, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Key Laboratory of Female Reproductive Health and Eugenics, Tianjin Medical University General Hospital, Tianjin, China
| | - Kan Wang
- Department of Gynecology and Obstetrics, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Key Laboratory of Female Reproductive Health and Eugenics, Tianjin Medical University General Hospital, Tianjin, China
| | - Zengyan Li
- Department of Gynecology and Obstetrics, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Key Laboratory of Female Reproductive Health and Eugenics, Tianjin Medical University General Hospital, Tianjin, China
| | - Cha Han
- Department of Gynecology and Obstetrics, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Key Laboratory of Female Reproductive Health and Eugenics, Tianjin Medical University General Hospital, Tianjin, China
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29
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Sadeghi-Alavijeh O, Chan MMY, Moochhala SH, Howles S, Gale DP, Böckenhauer D. Rare variants in the sodium-dependent phosphate transporter gene SLC34A3 explain missing heritability of urinary stone disease. Kidney Int 2023; 104:975-984. [PMID: 37414395 DOI: 10.1016/j.kint.2023.06.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 05/10/2023] [Accepted: 06/15/2023] [Indexed: 07/08/2023]
Abstract
Urinary stone disease (USD) is a major health burden affecting over 10% of the United Kingdom population. While stone disease is associated with lifestyle, genetic factors also strongly contribute. Common genetic variants at multiple loci from genome-wide association studies account for 5% of the estimated 45% heritability of the disorder. Here, we investigated the extent to which rare genetic variation contributes to the unexplained heritability of USD. Among participants of the United Kingdom 100,000-genome project, 374 unrelated individuals were identified and assigned diagnostic codes indicative of USD. Whole genome gene-based rare variant testing and polygenic risk scoring against a control population of 24,930 ancestry-matched controls was performed. We observed (and replicated in an independent dataset) exome-wide significant enrichment of monoallelic rare, predicted damaging variants in the SLC34A3 gene for a sodium-dependent phosphate transporter that were present in 5% cases compared with 1.6% of controls. This gene was previously associated with autosomal recessive disease. The effect on USD risk of having a qualifying SLC34A3 variant was greater than that of a standard deviation increase in polygenic risk derived from GWAS. Addition of the rare qualifying variants in SLC34A3 to a linear model including polygenic score increased the liability-adjusted heritability from 5.1% to 14.2% in the discovery cohort. We conclude that rare variants in SLC34A3 represent an important genetic risk factor for USD, with effect size intermediate between the fully penetrant rare variants linked with Mendelian disorders and common variants associated with USD. Thus, our findings explain some of the heritability unexplained by prior common variant genome-wide association studies.
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Affiliation(s)
| | - Melanie M Y Chan
- Department of Renal Medicine, University College London, London, UK
| | | | - Sarah Howles
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Daniel P Gale
- Department of Renal Medicine, University College London, London, UK.
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30
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Tato AM, Carrera N, García-Murias M, Shabaka A, Ávila A, Mora Mora MT, Rabasco C, Soto K, de la Prada Alvarez FJ, Fernández-Lorente L, Rodríguez-Moreno A, Huerta A, Mon C, García-Carro C, González Cabrera F, Navarro JAM, Romera A, Gutiérrez E, Villacorta J, de Lorenzo A, Avilés B, Garca-González MA, Fernández-Juárez G. Genetic testing in focal segmental glomerulosclerosis: in whom and when? Clin Kidney J 2023; 16:2011-2022. [PMID: 37915894 PMCID: PMC10616495 DOI: 10.1093/ckj/sfad193] [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: 03/09/2023] [Indexed: 11/03/2023] Open
Abstract
Background Genetic causes are increasingly recognized in patients with focal segmental glomerulosclerosis (FSGS), but it remains unclear which patients should undergo genetic study. Our objective was to determine the frequency and distribution of genetic variants in steroid-resistant nephrotic syndrome FSGS (SRNS-FSGS) and in FSGS of undetermined cause (FSGS-UC). Methods We performed targeted exome sequencing of 84 genes associated with glomerulopathy in patients with adult-onset SRNS-FSGS or FSGS-UC after ruling out secondary causes. Results Seventy-six patients met the study criteria; 24 presented with SRNS-FSGS and 52 with FSGS-UC. We detected FSGS-related disease-causing variants in 27/76 patients (35.5%). There were no differences between genetic and non-genetic causes in age, proteinuria, glomerular filtration rate, serum albumin, body mass index, hypertension, diabetes or family history. Hematuria was more prevalent among patients with genetic causes. We found 19 pathogenic variants in COL4A3-5 genes in 16 (29.3%) patients. NPHS2 mutations were identified in 6 (16.2%) patients. The remaining cases had variants affecting INF2, OCRL, ACTN4 genes or APOL1 high-risk alleles. FSGS-related genetic variants were more common in SRNS-FSGS than in FSGS-UC (41.7% vs 32.7%). Four SRNS-FSGS patients presented with NPHS2 disease-causing variants. COL4A variants were the most prevalent finding in FSGS-UC patients, with 12 patients carrying disease-causing variants in these genes. Conclusions FSGS-related variants were detected in a substantial number of patients with SRNS-FSGS or FSGS-UC, regardless of age of onset of disease or the patient's family history. In our experience, genetic testing should be performed in routine clinical practice for the diagnosis of this group of patients.
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Affiliation(s)
- Ana María Tato
- Department of Nephrology, Hospital Universitario Fundación Alcorcón, Alcorcón, Spain
| | - Noa Carrera
- Laboratorio de Nefroloxía (No. 11), Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Instituto de investigación sanitaria de Santiago de Compostela – IDIS, Santiago de Compostela, Spain
| | - Maria García-Murias
- Laboratorio de Nefroloxía (No. 11), Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Instituto de investigación sanitaria de Santiago de Compostela – IDIS, Santiago de Compostela, Spain
| | - Amir Shabaka
- Department of Nephrology, Hospital Universitario Fundación Alcorcón, Alcorcón, Spain
| | - Ana Ávila
- Department of Nephrology, Hospital Universitario Doctor Peset, Valencia, Spain
| | | | - Cristina Rabasco
- Department of Nephrology, Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Karina Soto
- Department of Nephrology, Hospital Fernando Fonseca, Lisbon, Portugal
| | | | | | | | - Ana Huerta
- Department of Nephrology, Hospital Universitario Puerta de Hierro, Majadahonda, Spain
| | - Carmen Mon
- Department of Nephrology, Hospital Universitario Severo Ochoa, Leganés, Spain
| | | | - Fayna González Cabrera
- Department of Nephrology, Hospital Universitario de Gran Canaria Doctor Negrín, Gran Canaria, Spain
| | | | - Ana Romera
- Department of Nephrology, Hospital de Ciudad Real, Ciudad Real, Spain
| | - Eduardo Gutiérrez
- Department of Nephrology, Hospital Universitario Doce de Octubre, Madrid, Spain
| | - Javier Villacorta
- Department of Nephrology, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | | | - Beatriz Avilés
- Department of Nephrology, Hospital Costa del Sol, Marbella, Spain
| | - Miguel Angel Garca-González
- Laboratorio de Nefroloxía (No. 11), Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Instituto de investigación sanitaria de Santiago de Compostela – IDIS, Santiago de Compostela, Spain
- Fundación Pública Galega de Medicina Xenómica-SERGAS, Complexo Hospitalario de Santiago de Compostela, Santiago de Compostela, Spain
| | - Gema Fernández-Juárez
- Department of Nephrology, Hospital Universitario La Paz, Madrid, Spain
- Instituto de Investigación de la Paz (IdIPAZ), Madrid, Spain
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31
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Mahrous NN, Jamous YF, Almatrafi AM, Fallatah DI, Theyab A, Alanati BH, Alsagaby SA, Alenazi MK, Khan MI, Hawsawi YM. A Current Landscape on Alport Syndrome Cases: Characterization, Therapy and Management Perspectives. Biomedicines 2023; 11:2762. [PMID: 37893135 PMCID: PMC10604007 DOI: 10.3390/biomedicines11102762] [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: 09/09/2023] [Revised: 09/30/2023] [Accepted: 10/05/2023] [Indexed: 10/29/2023] Open
Abstract
Alport syndrome (AS) is a rare genetic disorder categorized by the progressive loss of kidney function, sensorineural hearing loss and eye abnormalities. It occurs due to mutations in three genes that encode for the alpha chains of type IV collagen. Globally, the disease is classified based on the pattern of inheritance into X-linked AS (XLAS), which is caused by pathogenic variants in COL4A5, representing 80% of AS. Autosomal recessive AS (ARAS), caused by mutations in either COL4A3 or COL4A4, represents 15% of AS. Autosomal dominant AS (ADAS) is rare and has been recorded in 5% of all cases due to mutations in COL4A3 or COL4A4. This review provides updated knowledge about AS including its clinical and genetic characteristics in addition to available therapies that only slow the progression of the disease. It also focuses on reported cases in Saudi Arabia and their prevalence. Moreover, we shed light on advances in genetic technologies like gene editing using CRISPR/Cas9 technology, the need for an early diagnosis of AS and managing the progression of the disease. Eventually, we provide a few recommendations for disease management, particularly in regions like Saudi Arabia where consanguineous marriages increase the risk.
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Affiliation(s)
- Nahed N. Mahrous
- Department of Biological Sciences, College of Science, University of Hafr Al-Batin, Hafr Al-Batin 39524, Saudi Arabia;
| | - Yahya F. Jamous
- The National Center of Vaccines and Bioprocessing, King Abdulaziz City for Science and Technology, Riyadh 12354, Saudi Arabia;
| | - Ahmad M. Almatrafi
- Department of Biological Sciences, College of Science, Taibah University, Madinah 42353, Saudi Arabia;
| | - Deema I. Fallatah
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia;
| | - Abdulrahman Theyab
- Department of Laboratory and Blood Bank, Security Forces Hospital, Makkah 11481, Saudi Arabia;
- Department of Biochemistry & Molecular Medicine, College of Medicine, Al-Faisal University, P.O. Box 50927, Riyadh 11533, Saudi Arabia
| | - Bayan H. Alanati
- Center for Synthetic Microbiology, Bioinformatics Core Facility, University of Marburg, 35032 Marburg, Germany;
| | - Suliman A. Alsagaby
- Department of Medicinal Laboratory Sciences, College of Applied Medical Sciences, Majmaah University, Al-Majmaah 11952, Saudi Arabia;
| | - Munifa K. Alenazi
- Research Center, King Faisal Specialist Hospital and Research Center, P.O. Box 40047, Jeddah 21499, Saudi Arabia; (M.K.A.); (M.I.K.)
| | - Mohammed I. Khan
- Research Center, King Faisal Specialist Hospital and Research Center, P.O. Box 40047, Jeddah 21499, Saudi Arabia; (M.K.A.); (M.I.K.)
| | - Yousef M. Hawsawi
- Department of Biochemistry & Molecular Medicine, College of Medicine, Al-Faisal University, P.O. Box 50927, Riyadh 11533, Saudi Arabia
- Research Center, King Faisal Specialist Hospital and Research Center, P.O. Box 40047, Jeddah 21499, Saudi Arabia; (M.K.A.); (M.I.K.)
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Schnuelle P. Renal Biopsy for Diagnosis in Kidney Disease: Indication, Technique, and Safety. J Clin Med 2023; 12:6424. [PMID: 37835066 PMCID: PMC10573674 DOI: 10.3390/jcm12196424] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 09/29/2023] [Accepted: 10/04/2023] [Indexed: 10/15/2023] Open
Abstract
Renal biopsies are the gold standard for diagnosis, staging, and prognosis of underlying parenchymal kidney disease. This article provides an overview of the current indications and highlights ways to reduce bleeding complications in order to achieve optimal diagnostic yield with minimal risk to the patient. Novel indications have emerged from the increasing use of new molecularly targeted oncologic therapies in recent years, which often induce immune-mediated renal disease. On the other hand, the detection of specific antibodies against target antigens on podocytes in the sera of patients with new-onset nephrotic syndrome has now relativized the indication for biopsy in membranous nephropathy. The use of semi-automatic spring-loaded biopsy devices and real-time ultrasound considerably declined the complication rate and is the current standard. Percutaneous renal biopsies are overall a safe procedure if contraindications are considered. A coagulation disorder needs to be excluded beforehand, and an elevated blood pressure must be reduced to the normotensive range with medications. A laparoscopic approach or a radiology interventional procedure through the internal jugular vein may be considered for obtaining a kidney tissue sample if there is an urgent indication and a bleeding tendency cannot be adequately corrected. Major bleeding after a percutaneous renal biopsy can usually be managed with selective arterial embolization of the injured renal vessel. The use of a 16-gauge needle is the most reasonable compromise between diagnostic benefit and risk of complication. In the routine diagnostic, the biopsy specimen is examined with light microscopy, immunohistochemistry, and electron microscopy. Combination with modern molecular pathology techniques will contribute to more precise insights into the development and progression of kidney disease, which will likely refine future treatments in nephrology.
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Affiliation(s)
- Peter Schnuelle
- Center for Renal Diseases Weinheim, Academic Teaching Practice of the University Medical Center Mannheim, University of Heidelberg, D-69469 Weinheim, Germany
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33
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Sargazi M, Dehghani S, Dahmardeh M, Mohammadi SO. Ocular Manifestations of Alport Syndrome: Report and Comparison of Two Cases. Cureus 2023; 15:e47373. [PMID: 38022159 PMCID: PMC10657510 DOI: 10.7759/cureus.47373] [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] [Accepted: 10/19/2023] [Indexed: 12/01/2023] Open
Abstract
We report two cases of Alport syndrome and compare the clinical presentations and imaging findings in these cases. The clinical examination consisted of best-corrected visual acuity (BCVA), direct ophthalmoscopy, and slit-lamp examination. Macular optical coherence tomography (OCT) and anterior segment OCT (AS-OCT) and were utilized to document the details of the anterior and posterior segment pathologies. In order to evaluate systemic presentations of Alport syndrome, nephrology, and otolaryngology were consulted for each patient. In this study, the first case was a 27-year-old female with progressive myopia, anterior lenticonus, and temporal retinal thinning found in the ocular examination that led to the diagnosis of Alport syndrome. She underwent clear lens extraction and intraocular lens implantation, restoring acceptable visual acuity. The second case was a 20-year-old male patient with low visual acuity, severe bilateral anterior lenticonus, bilateral cataract, and temporal retinal thinning. The patient later developed renal failure and is a candidate for kidney transplantation. In this case report, progressive renal failure, hearing loss, and ocular abnormalities were all observed. This is consistent with previously reported cases given the typical characteristics of Alport syndrome, a rare inherited disease. The severity of those characteristics was higher in the male subject, a finding also consistent with prior reports indicating that males are usually affected more frequently and more severely than females, given that Alport syndrome is generally inherited as an X-linked disorder. Additionally, anterior segment and macular OCTs seemed to be of considerable significance in the early diagnosis of Alport syndrome given the typical ocular manifestations e.g. anterior lenticonus or temporal retinal atrophy.
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Affiliation(s)
- Meisam Sargazi
- Ophthalmology, Zahedan University of Medical Sciences, Zahedan, IRN
| | - Shima Dehghani
- Ophthalmology, Zahedan University of Medical Sciences, Zahedan, IRN
| | - Mina Dahmardeh
- Ophthalmology, Zahedan University of Medical Sciences, Zahedan, IRN
| | - Seyed Omid Mohammadi
- Ophthalmology, Burnett School of Medicine at Texas Christian University, Fort Worth, USA
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Tong J, Zheng Q, Gu X, Weng Q, Yu S, Fang Z, Jafar Hussain HM, Xu J, Ren H, Chen N, Xie J. COL4A3 Mutation Induced Podocyte Apoptosis by Dysregulation of NADPH Oxidase 4 and MMP-2. Kidney Int Rep 2023; 8:1864-1874. [PMID: 37705901 PMCID: PMC10496016 DOI: 10.1016/j.ekir.2023.06.007] [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: 09/27/2022] [Revised: 05/15/2023] [Accepted: 06/05/2023] [Indexed: 09/15/2023] Open
Abstract
Introduction Podocyte apoptosis is a common mechanism driving progression in Alport syndrome (AS). This study aimed to investigate the mechanism of podocyte apoptosis caused by COL4A3 mutations. Methods We recruited patients with autosomal dominant AS (ADAS). Patients with minimal change disease (MCD) were recruited as controls. Microarray analysis was carried out on isolated glomeruli from the patients and validated. Then, corresponding mutant human podocytes (p.C1616Y) and 129 mice (p.C1615Y, the murine homolog to the human p.C1616Y) were constructed. The highest differentially expressed genes (DEGs) from microarray analysis were validated in transgenic mice and podocytes before and after administration of MMP-2 inhibitor (SB-3CT) and NOX4 inhibitor (GKT137831). We further validated NOX4/MMP-2/apoptosis pathway by real-time polymerase chain reaction (PCR), immunohistochemistry, and western blot in renal tissues from the ADAS patients. Results Using microarray analysis, we observed that DEGs, including NOX4/H2O2, MMP-2, and podocyte apoptosis-related genes were significantly upregulated. These genes were validated by real-time PCR, histologic analysis, and western blot in corresponding mutant human podocyte (p.C1616Y) and/or mice models (p.C1615Y). Moreover, we found podocyte apoptosis was abrogated and MMP-2 expression was down-regulated both in vivo and in vitro by NOX4 inhibition, urinary albumin-to-creatinine ratio, 24-hour proteinuria; and renal pathologic lesion was attenuated by NOX4 inhibition in vivo. Furthermore, podocyte apoptosis was attenuated whereas NOX4 expression remained the same by inhibition of MMP-2 both in vivo and in vitro. Conclusion These results indicated that NOX4 might induce podocyte apoptosis through the regulation of MMP-2 in patients with COL4A3 mutations. Our findings provided new insights into the mechanism of ADAS.
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Affiliation(s)
- Jun Tong
- Department of Nephrology, Institute of Nephrology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Qimin Zheng
- Department of Nephrology, Institute of Nephrology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Xiangchen Gu
- Department of Nephrology, Institute of Nephrology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Qinjie Weng
- Department of Nephrology, Institute of Nephrology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Shuwen Yu
- Department of Nephrology, Institute of Nephrology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Zhengying Fang
- Department of Nephrology, Institute of Nephrology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Hafiz Muhammad Jafar Hussain
- Department of Nephrology, Institute of Nephrology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Jing Xu
- Department of Nephrology, Institute of Nephrology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Hong Ren
- Department of Nephrology, Institute of Nephrology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Nan Chen
- Department of Nephrology, Institute of Nephrology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
| | - Jingyuan Xie
- Department of Nephrology, Institute of Nephrology, Shanghai Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China
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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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Kermond-Marino A, Weng A, Xi Zhang SK, Tran Z, Huang M, Savige J. Population Frequency of Undiagnosed Fabry Disease in the General Population. Kidney Int Rep 2023; 8:1373-1379. [PMID: 37441486 PMCID: PMC10334396 DOI: 10.1016/j.ekir.2023.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 04/07/2023] [Accepted: 04/10/2023] [Indexed: 07/15/2023] Open
Abstract
Introduction Fabry disease is an X-linked disorder that results from pathogenic GLA variants and can now be treated. Most studies of its population frequency have examined only males or attendees at kidney failure or cardiac clinics. This study determined the prevalence of undiagnosed Fabry disease from predicted pathogenic GLA variants in the general population. Methods The Genome Aggregation Database (gnomAD) was examined for predicted pathogenic GLA variants based on variant rarity (≤5), and transcript effect in 4 computational tools (CADD >20, PP2 >0.95, SIFT <0.05, Mutation Taster - Disease-causing) and amino acid conservation in vertebrates in a Clustal. Results Predicted pathogenic variants in GLA occurred in 1 in 3225 of the gnomAD population and 1 in 3478 of its control subset. Predicted pathogenic variants were more common in women than expected (3.1:1), which is consistent with men being excluded from gnomAD because of Fabry complications. Predicted pathogenic variants were not found in members of this cohort with South Asian, Ashkenazim, or Finnish ancestries. Variants identified as pathogenic in the Fabry database were found in 1 in 2651 individuals of the gnomAD database and pathogenic variants from ClinVar in 1 in 4420. Discussion The population frequency of 1 in 3225 for undiagnosed men and women with Fabry disease still represents an underestimate because our pathogenicity criteria were rigorous, the cohort did not include already-diagnosed individuals, and whole exome sequencing does not detect intronic variants and large deletions. This study confirms that Fabry disease is more common than previously recognized and still underdiagnosed especially in women.
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Affiliation(s)
- Amalia Kermond-Marino
- Department of Medicine, Melbourne Health and Northern Health, The University of Melbourne Victoria, Australia
| | - Annie Weng
- Department of Medicine, Melbourne Health and Northern Health, The University of Melbourne Victoria, Australia
| | - Selina Kai Xi Zhang
- Department of Medicine, Melbourne Health and Northern Health, The University of Melbourne Victoria, Australia
| | - Zac Tran
- Department of Medicine, Melbourne Health and Northern Health, The University of Melbourne Victoria, Australia
| | - Mary Huang
- Department of Medicine, Melbourne Health and Northern Health, The University of Melbourne Victoria, Australia
| | - Judy Savige
- Department of Medicine, Melbourne Health and Northern Health, The University of Melbourne Victoria, Australia
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Cosgrove D, Gratton MA, Madison J, Vosik D, Samuelson G, Meehan D, Delimont D, Phillips G, Smyth B, Pramparo T, Jarocki D, Nguyen M, Komers R, Jenkinson C. Dual inhibition of the endothelin and angiotensin receptor ameliorates renal and inner ear pathologies in Alport mice. J Pathol 2023; 260:353-364. [PMID: 37256677 PMCID: PMC10330771 DOI: 10.1002/path.6087] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 03/08/2023] [Accepted: 04/04/2023] [Indexed: 06/01/2023]
Abstract
Alport syndrome (AS), a type IV collagen disorder, leads to glomerular disease and, in some patients, hearing loss. AS is treated with inhibitors of the renin-angiotensin system; however, a need exists for novel therapies, especially those addressing both major pathologies. Sparsentan is a single-molecule dual endothelin type-A and angiotensin II type 1 receptor antagonist (DEARA) under clinical development for focal segmental glomerulosclerosis and IgA nephropathy. We report the ability of sparsentan to ameliorate both renal and inner ear pathologies in an autosomal-recessive Alport mouse model. Sparsentan significantly delayed onset of glomerulosclerosis, interstitial fibrosis, proteinuria, and glomerular filtration rate decline. Sparsentan attenuated glomerular basement membrane defects, blunted mesangial filopodial invasion into the glomerular capillaries, increased lifespan more than losartan, and lessened changes in profibrotic/pro-inflammatory gene pathways in both the glomerular and the renal cortical compartments. Notably, treatment with sparsentan, but not losartan, prevented accumulation of extracellular matrix in the strial capillary basement membranes in the inner ear and reduced susceptibility to hearing loss. Improvements in lifespan and in renal and strial pathology were observed even when sparsentan was initiated after development of renal pathologies. These findings suggest that sparsentan may address both renal and hearing pathologies in Alport syndrome patients. © 2023 Travere Therapeutics, Inc and The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Dominic Cosgrove
- Center for Sensory Neuroscience, Boys Town National Research Hospital, Omaha, NE, USA
| | - Michael Anne Gratton
- Department of Otolaryngology, Washington University in St. Louis, St. Louis, MO, USA
| | - Jacob Madison
- Center for Sensory Neuroscience, Boys Town National Research Hospital, Omaha, NE, USA
| | - Denise Vosik
- Center for Sensory Neuroscience, Boys Town National Research Hospital, Omaha, NE, USA
| | - Gina Samuelson
- Center for Sensory Neuroscience, Boys Town National Research Hospital, Omaha, NE, USA
| | - Daniel Meehan
- Center for Sensory Neuroscience, Boys Town National Research Hospital, Omaha, NE, USA
| | - Duane Delimont
- Center for Sensory Neuroscience, Boys Town National Research Hospital, Omaha, NE, USA
| | - Grady Phillips
- Department of Otolaryngology, Washington University in St. Louis, St. Louis, MO, USA
| | - Brendan Smyth
- Department of Otolaryngology, Washington University in St. Louis, St. Louis, MO, USA
| | | | - Diana Jarocki
- Department of Otolaryngology, Washington University in St. Louis, St. Louis, MO, USA
| | - Mai Nguyen
- Travere Therapeutics, San Diego, CA, USA
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Savige J, Weinstock BA. What patients want to know about genetic testing for kidney disease. Front Med (Lausanne) 2023; 10:1201712. [PMID: 37342499 PMCID: PMC10277795 DOI: 10.3389/fmed.2023.1201712] [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: 04/07/2023] [Accepted: 05/03/2023] [Indexed: 06/23/2023] Open
Abstract
Previously, genetic kidney disease was often recognised when family members shared clinical features. Now, many genetic kidney diseases are diagnosed when testing demonstrates a pathogenic variant in a gene associated with the disease. Detection of a genetic variant also identifies the mode of inheritance, and suggests family members at risk. The genetic diagnosis has additional advantages for patients and their doctors even when no specific treatment is available since it often indicates likely complications in other organs, the clinical course, and management strategies. Generally, informed consent is required for genetic testing because the result provides "certainty" with implications for the patient, and their family, and possibly for employment, and for life and medical insurance, as well as having social, ethical, and financial consequences. Patients want to be provided with a copy of their genetic test result in a format that is comprehensible and to have the result explained. Their at-risk family members should be sought out and offered genetic testing too. Patients who allow the sharing of their anonymised results in registries help advance everyone's understanding of these diseases and expedite a diagnosis in other families. Patient Support Groups not only help normalise the disease but also educate patients, and update them on recent advances and new treatments. Some registries encourage patients to themselves submit their genetic variants, clinical features and response to treatment. More and more often, patients may volunteer for clinical trials of novel therapies including some that depend on a genetic diagnosis or variant type.
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Affiliation(s)
- Judy Savige
- Department of Medicine (Melbourne Health and Northern Health), Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
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39
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Doctor GT, Gale DP, Chan MM. Genomics in the kidney clinic. Clin Med (Lond) 2023; 23:246-249. [PMID: 37236798 PMCID: PMC11046554 DOI: 10.7861/clinmed.2023-rm2] [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] [Indexed: 05/28/2023]
Abstract
Inherited diseases are a frequent cause of end-stage kidney disease and often seen in the kidney clinic. Clinical genomic testing is increasingly available in the UK and eligible patients in England can be referred through the NHS Genomic Medicine Service. Testing is useful for diagnosis, prognostication and management of conditions such as autosomal dominant polycystic kidney disease (ADPKD), Alport syndrome, autosomal dominant tubulointerstitial kidney disease (ADTKD) and focal segmental glomerulosclerosis (FSGS). As more patients undergo genomic testing and newer technologies such as whole genome sequencing are applied, we are developing a greater appreciation of the full phenotypic spectrum of inherited kidney diseases and the challenges associated with the interpretation of clinically significant variants.
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Thomas CP, Daloul R, Lentine KL, Gohh R, Anand PM, Rasouly HM, Sharfuddin AA, Schlondorff JS, Rodig NM, Freese ME, Garg N, Lee BK, Caliskan Y. Genetic evaluation of living kidney donor candidates: A review and recommendations for best practices. Am J Transplant 2023; 23:597-607. [PMID: 36868514 DOI: 10.1016/j.ajt.2023.02.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/25/2023] [Accepted: 02/20/2023] [Indexed: 03/05/2023]
Abstract
The growing accessibility and falling costs of genetic sequencing techniques has expanded the utilization of genetic testing in clinical practice. For living kidney donation, genetic evaluation has been increasingly used to identify genetic kidney disease in potential candidates, especially in those of younger ages. However, genetic testing on asymptomatic living kidney donors remains fraught with many challenges and uncertainties. Not all transplant practitioners are aware of the limitations of genetic testing, are comfortable with selecting testing methods, comprehending test results, or providing counsel, and many do not have access to a renal genetic counselor or a clinical geneticist. Although genetic testing can be a valuable tool in living kidney donor evaluation, its overall benefit in donor evaluation has not been demonstrated and it can also lead to confusion, inappropriate donor exclusion, or misleading reassurance. Until more published data become available, this practice resource should provide guidance for centers and transplant practitioners on the responsible use of genetic testing in the evaluation of living kidney donor candidates.
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Affiliation(s)
- Christie P Thomas
- Department of of Internal Medicine and Iowa Institute of Human Genetics, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA; VA Medical Center, Iowa City, Iowa, USA.
| | - Reem Daloul
- Division of Nephrology, Department of Internal Medicine, Allegheny General Hospital, Pittsburgh, Pennsylvania, USA
| | - Krista L Lentine
- Saint Louis University Transplant Center, SSM Health Saint Louis University Hospital, St. Louis, Missouri, USA
| | - Reginald Gohh
- Department of Medicine, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Prince M Anand
- Mid-Carolinas Transplant Center, Medical University of South Carolina, Lancaster, South Carolina, USA
| | - Hila Milo Rasouly
- Center for Precision Medicine and Genomics, Department of Medicine, Columbia University, New York City, New York, USA
| | - Asif A Sharfuddin
- Division of Nephrology and Transplant, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Johannes S Schlondorff
- Department of Internal Medicine, Ohio State University Medical Center, Columbus, Ohio, USA
| | - Nancy M Rodig
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Margaret E Freese
- Department of of Internal Medicine and Iowa Institute of Human Genetics, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Neetika Garg
- Division of Nephrology, Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Brian K Lee
- Kidney/Pancreas Transplant Center, Dell Seton Medical Center, University of Texas at Austin, Austin, Texas, USA
| | - Yasar Caliskan
- Saint Louis University Transplant Center, SSM Health Saint Louis University Hospital, St. Louis, Missouri, USA
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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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Groen In 't Woud S, Rood IM, Steenbergen E, Willemsen B, Dijkman HB, van Geel M, Schoots J, Wetzels JFM, Lugtenberg D, Deegens JKJ, Bongers EMHF. Kidney Disease Associated With Mono-allelic COL4A3 and COL4A4 Variants: A Case Series of 17 Families. Kidney Med 2023; 5:100607. [PMID: 36925663 PMCID: PMC10011433 DOI: 10.1016/j.xkme.2023.100607] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Rationale & Objective Mono-allelic variants in COL4A3 and COL4A4 (COL4A3/COL4A4) have been identified in a spectrum of glomerular basement membrane nephropathies, including thin basement membrane nephropathy and autosomal dominant Alport syndrome. With the increasing use of next generation sequencing, mono-allelic COL4A3/COL4A4 variants are detected more frequently, but phenotypic heterogeneity impedes counseling. We aimed to investigate the phenotypic spectrum, kidney biopsy results, and segregation patterns of patients with mono-allelic COL4A3/COL4A4 variants identified by whole exome sequencing. Study Design Case series. Setting & Participants We evaluated clinical and pathologic characteristics of 17 Dutch index patients with mono-allelic variants in COL4A3/COL4A4 detected by diagnostic whole exome sequencing and 25 affected family members with variants confirmed by Sanger sequencing. Results Eight different mono-allelic COL4A3/COL4A4 variants were identified across members of 11 families, comprising 7 glycine substituted missense variants and 1 frameshift variant. All index patients had microscopic hematuria at clinical presentation (median age 43 years) and 14 had (micro)albuminuria/proteinuria. All family members showed co-segregation of the variant with at least hematuria. At end of follow-up of all 42 individuals (median age 54 years), 16/42 patients had kidney function impairment, of whom 6 had kidney failure. Reports of kidney biopsies of 14 patients described thin basement membrane nephropathy, focal segmental glomerulosclerosis, minimal change lesions, and Alport syndrome. Electron microscopy images of 7 patients showed a significantly thinner glomerular basement membrane compared with images of patients with idiopathic focal segmental glomerulosclerosis and other hereditary glomerular diseases. No genotype-phenotype correlations could be established. Limitations Retrospective design, ascertainment bias toward severe kidney phenotypes, and familial hematuria. Conclusions This study confirms the wide phenotypic spectrum associated with mono-allelic COL4A3/COL4A4 variants, extending from isolated microscopic hematuria to kidney failure with high intra- and interfamilial variability.
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Affiliation(s)
- Sander Groen In 't Woud
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department for Health Evidence, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ilse M Rood
- Department of Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Eric Steenbergen
- Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Brigith Willemsen
- Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Henry B Dijkman
- Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Michel van Geel
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Jeroen Schoots
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jack F M Wetzels
- Department of Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Dorien Lugtenberg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen K J Deegens
- Department of Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ernie M H F Bongers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
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Reiterová J, Tesař V. Current and Future Therapeutical Options in Alport Syndrome. Int J Mol Sci 2023; 24:5522. [PMID: 36982595 PMCID: PMC10056269 DOI: 10.3390/ijms24065522] [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: 01/02/2023] [Revised: 03/07/2023] [Accepted: 03/09/2023] [Indexed: 03/18/2023] Open
Abstract
Alport syndrome (AS) is a hereditary kidney disease caused by pathogenic variants in COL4A3 and COL4A4 genes with autosomal recessive or autosomal dominant transmission or in the COL4A5 gene with X-linked inheritance. Digenic inheritance was also described. Clinically it is associated with microscopic hematuria, followed by proteinuria and chronic renal insufficiency with end-stage renal disease in young adults. Nowadays, there is no curative treatment available. The inhibitors of RAS (renin-angiotensin system) since childhood slow the progression of the disease. Sodium-glucose cotransporter-2 inhibitors seem to be promising drugs from DAPA-CKD (dapagliflozin-chronic kidney disease) study, but only a limited number of patients with Alport syndrome was included. Endothelin type A receptor and angiotensin II type 1 receptor combined inhibitors, and lipid-lowering agents are used in ongoing studies in patients with AS and focal segmental glomerulosclerosis (FSGS). Hydroxychloroquine in AS is studied in a clinical trial in China. Molecular genetic diagnosis of AS is crucial not only for prognosis prediction but also for future therapeutic options. Different types of mutations will require various types of gene, RNA, or protein therapy to improve the function, the of final protein product.
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Affiliation(s)
- Jana Reiterová
- Department of Nephrology, First Faculty of Medicine, Charles University, General University Hospital in Prague, 128 08 Prague, Czech Republic
- First Faculty of Medicine, Institute of Biology and Medical Genetics, Charles University, General University Hospital in Prague, 128 08 Prague, Czech Republic
| | - Vladimír Tesař
- Department of Nephrology, First Faculty of Medicine, Charles University, General University Hospital in Prague, 128 08 Prague, Czech Republic
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Gregorio VD, Caparali B, Shojaei A, Ricardo S, Barua M. Alport Syndrome: Clinical Spectrum and Therapeutic Advances. Kidney Med 2023; 5:100631. [PMID: 37122389 PMCID: PMC10131117 DOI: 10.1016/j.xkme.2023.100631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023] Open
Abstract
Alport syndrome is a hereditary disorder characterized by kidney disease, ocular abnormalities, and sensorineural hearing loss. Work in understanding the cause of Alport syndrome and the molecular composition of the glomerular basement membrane ultimately led to the identification of COL4A3, COL4A4 (both on chromosome 2q36), and COL4A5 (chromosome Xq22), encoding the α3, α4, and α5 chains of type IV collagen, as the responsible genes. Subsequent studies suggested that autosomal recessive Alport syndrome and males with X-linked Alport syndrome have more severe disease, whereas autosomal dominant Alport syndrome and females with X-linked Alport syndrome have more variability. Variant type is also influential-protein-truncating variants in autosomal recessive Alport syndrome or males with X-linked Alport syndrome often present with severe symptoms, characterized by kidney failure, extrarenal manifestations, and lack of the α3-α4-α5(IV) network. By contrast, mild-moderate forms from missense variants display α3-α4-α5(IV) in the glomerular basement membrane and are associated with protracted kidney involvement without extrarenal manifestations. Regardless of type, therapeutic intervention for kidney involvement is focused on early initiation of angiotensin-converting enzyme inhibitors. There are several therapies under investigation including sodium/glucose cotransporter 2 inhibitors, aminoglycoside analogs, endothelin type A antagonists, lipid-modifying drugs, and hydroxychloroquine, although targeting the underlying defect through gene therapy remains in preclinical stages.
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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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Plevova P, Indrakova J, Savige J, Kuhnova P, Tvrda P, Cerna D, Hilscherova S, Kudrejova M, Polendova D, Jaklova R, Langova M, Jahnova H, Lastuvkova J, Dusek J, Gut J, Vlckova M, Solarova P, Kreckova G, Kantorova E, Soukalova J, Slavkovsky R, Zapletalova J, Tichy T, Thomasova D. A founder COL4A4 pathogenic variant resulting in autosomal recessive Alport syndrome accounts for most genetic kidney failure in Romani people. Front Med (Lausanne) 2023; 10:1096869. [PMID: 36844206 PMCID: PMC9948603 DOI: 10.3389/fmed.2023.1096869] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 01/11/2023] [Indexed: 02/10/2023] Open
Abstract
Introduction Romani people have a high prevalence of kidney failure. This study examined a Romani cohort for pathogenic variants in the COL4A3, COL4A4, and COL4A5 genes that are affected in Alport syndrome (AS), a common cause of genetic kidney disease, characterized by hematuria, proteinuria, end-stage kidney failure, hearing loss, and eye anomalies. Materials and methods The study included 57 Romani from different families with clinical features that suggested AS who underwent next-generation sequencing (NGS) of the COL4A3, COL4A4, and COL4A5 genes, and 83 family members. Results In total, 27 Romani (19%) had autosomal recessive AS caused by a homozygous pathogenic c.1598G>A, p.Gly533Asp variant in COL4A4 (n = 20) or a homozygous c.415G>C, p.Gly139Arg variant in COL4A3 (n = 7). For p.Gly533Asp, 12 (80%) had macroscopic hematuria, 12 (63%) developed end-stage kidney failure at a median age of 22 years, and 13 (67%) had hearing loss. For p.Gly139Arg, none had macroscopic hematuria (p = 0.023), three (50%) had end-stage kidney failure by a median age of 42 years (p = 0.653), and five (83%) had hearing loss (p = 0.367). The p.Gly533Asp variant was associated with a more severe phenotype than p.Gly139Arg, with an earlier age at end-stage kidney failure and more macroscopic hematuria. Microscopic hematuria was very common in heterozygotes with both p.Gly533Asp (91%) and p.Gly139Arg (92%). Conclusion These two founder variants contribute to the high prevalence of kidney failure in Czech Romani. The estimated population frequency of autosomal recessive AS from these variants and consanguinity by descent is at least 1:11,000 in Czech Romani. This corresponds to a population frequency of autosomal dominant AS from these two variants alone of 1%. Romani with persistent hematuria should be offered genetic testing.
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Affiliation(s)
- Pavlina Plevova
- Department of Clinical and Molecular Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czechia,Department of Biomedical Sciences, Faculty of Medicine, University of Ostrava, Ostrava, Czechia,*Correspondence: Pavlina Plevova,
| | - Jana Indrakova
- Department of Clinical and Molecular Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czechia
| | - Judy Savige
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Royal Melbourne Hospital, Melbourne, Australia
| | - Petra Kuhnova
- Department of Clinical and Molecular Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czechia
| | - Petra Tvrda
- Department of Clinical and Molecular Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czechia
| | - Dita Cerna
- Department of Clinical and Molecular Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czechia
| | - Sarka Hilscherova
- Department of Clinical and Molecular Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czechia
| | - Monika Kudrejova
- Department of Clinical and Molecular Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czechia
| | - Daniela Polendova
- Department of Medical Genetics, Faculty of Medicine in Plzeň, Charles University and University Hospital Plzeň, Plzeň, Czechia
| | - Radka Jaklova
- Department of Medical Genetics, Faculty of Medicine in Plzeň, Charles University and University Hospital Plzeň, Plzeň, Czechia
| | - Martina Langova
- Department of Medical Genetics, Thomayer University Hospital, Prague, Czechia
| | - Helena Jahnova
- Department of Pediatrics, Third Faculty of Medicine, Charles University and University Hospital Královské Vinohrady, Prague, Czechia
| | - Jana Lastuvkova
- Department of Medical Genetics, Krajská zdravotní, a.s., Masaryk Hospital in Ústí nad Labem, Ústí nad Labem, Czechia
| | - Jiri Dusek
- Department of Pediatrics, 2nd Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czechia
| | - Josef Gut
- Department of Pediatrics, Hospital Česká Lípa, Česká Lípa, Czechia
| | - Marketa Vlckova
- Department of Biology and Medical Genetics, 2nd Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czechia
| | - Pavla Solarova
- Department of Medical Genetics, University Hospital Hradec Králové, Hradec Králové, Czechia
| | | | - Eva Kantorova
- Department of Medical Genetics, Hospital České Budějovice a.s., České Budějovice, Czechia
| | - Jana Soukalova
- Department of Medical Genetics and Genomics, University Hospital Brno, Brno, Czechia
| | - Rastislav Slavkovsky
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, Olomouc, Czechia
| | - Jana Zapletalova
- Department of Medical Biophysics, Faculty of Medicine and Dentistry, Palacký University Olomouc, Olomouc, Czechia
| | - Tomas Tichy
- Institute of Clinical and Molecular Pathology, Faculty of Medicine and Dentistry, Palacký University Olomouc, Olomouc, Czechia
| | - Dana Thomasova
- Department of Biology and Medical Genetics, 2nd Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czechia
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47
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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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48
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Horaček M, Martić TN, Šenjug P, Perica MŠ, Oroz M, Kuzmac S, Klarić D, Glavina Durdov M, Saraga M, Milošević D, Batinić D, Ćorić M, Paić F, Ljubanović DG. Clinical and histopathological characteristics of COL4A3 c.2881+1G>A variant causing Alport spectrum disorders in Croatian population. BIOMOLECULES AND BIOMEDICINE 2023; 23:89-100. [PMID: 35880347 PMCID: PMC9901899 DOI: 10.17305/bjbms.2022.7567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 06/28/2022] [Indexed: 02/08/2023]
Abstract
Alport syndrome (AS) and thin basement membrane nephropathy (TBMN) are part of the spectrum of kidney disorders caused by pathogenic variants in α3, α4, or α5 chains of the collagen type IV, the major structural component of the glomerular basement membrane (GBM). Using targeted next-generation sequencing (NGS), 34 AS/TBMN patients (58.8% male) from 12 unrelated families were found positive for heterozygous c.2881+1G>A variant of the COL4A3gene, that is considered disease-causing. All patients were from the continental or island part of Croatia. Clinical, laboratory, and histopathological data collected from the medical records were analyzed and compared to understand the clinical course and prognosis of the affected patients. At the time of biopsy or first clinical evaluation, the mean age was 31 years (median: 35 years; range: 1 - 72 years). Hematuria was present in 33 patients (97.1%) and 19 (55.9%) patients had proteinuria. There were 6 (17.6%) patients with hearing loss, 4 (11.8%) with ocular lesions, and 11 (32.4%) with hypertension. Twenty-three (67.6%) patients had proteinuria at follow-up, and 5 (14.7%) patients with the median age of 48 years (range: 27-55) progressed to kidney failure, started dialysis, or underwent kidney transplantation. Of the 13 patients who underwent kidney biopsy, 4 (30.8%) developed focal segmental glomerulosclerosis (FSGS), and 8 (66.7%) showed lamellation of the GBM, including all patients with FSGS. It is essential to conduct a detailed analysis of each collagen type IV genetic variant to optimize the prognosis and therapeutic approach for affected patients.
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Affiliation(s)
- Matija Horaček
- Institute of Pathology, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Tamara Nikuševa Martić
- Department of Medical Biology and Genetics, School of Medicine, University of Zagreb, Zagreb, Croatia,Correspondence to Tamara Nikuševa Martić:
| | - Petar Šenjug
- Department of Nephropatology and Electron Microscopy, Dubrava University Hospital, Zagreb, Croatia
| | | | - Maja Oroz
- Department of Gynecology and Obstetrics, Clinical Hospital “Sveti Duh”, Zagreb, Croatia
| | - Sania Kuzmac
- Clinical Department of Pathology and Cytology, University Hospital Centre Zagreb, Zagreb, Croatia
| | - Dragan Klarić
- Department of Nephrology, General Hospital Zadar, Zadar, Croatia
| | | | - Marijan Saraga
- Department of Pediatrics, University Hospital Split, Split, Croatia
| | - Danko Milošević
- Department of Pediatrics, University Hospital Centre Zagreb, Zagreb, Croatia
| | - Danica Batinić
- Pediatric ordination dr. Danica Batinić, Zagreb, Croatia
| | - Marijana Ćorić
- Institute of Pathology, School of Medicine, University of Zagreb, Zagreb, Croatia,Clinical Department of Pathology and Cytology, University Hospital Centre Zagreb, Zagreb, Croatia
| | - Frane Paić
- Department of Medical Biology and Genetics, School of Medicine, University of Zagreb, Zagreb, Croatia,Laboratory for Epigenetics and Molecular Medicine, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Danica Galešić Ljubanović
- Institute of Pathology, School of Medicine, University of Zagreb, Zagreb, Croatia,Department of Nephropatology and Electron Microscopy, Dubrava University Hospital, Zagreb, Croatia
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49
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Qiu J, Chi H, Gan C, Zhou X, Chen D, Yang Q, Chen Y, Wang M, Yang H, Jiang W, Li Q. A high-impact FN1 variant correlates with fibronectin-mediated glomerulopathy via decreased binding to collagen type IV. Pathology 2023; 55:498-507. [PMID: 36774238 DOI: 10.1016/j.pathol.2022.10.016] [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: 04/11/2022] [Revised: 10/24/2022] [Accepted: 10/31/2022] [Indexed: 01/22/2023]
Abstract
The glomerular basement membrane (GBM) consists of laminins, collagen IV, nidogens, and fibronectin and is essential for filtration barrier integrity in the kidney. Critically, structural and functional abnormalities in the GBM are involved in chronic kidney disease (CKD) occurrence and development. Fibronectin is encoded by FN1 and is essential for podocyte-podocyte and podocyte-matrix interactions. However, disrupted or disordered fibronectin occurs in many kidney diseases. In this study, we identified a novel mutation (c.3415G>A) in FN1 that causes glomerular fibronectin-specific deposition in a gain-of-function manner, that may be associated with thin basement membrane nephropathy (TBMN) and expand the spectrum of phenotypes seen in glomerulopathy with fibronectin deposits (GFND). Our studies confirmed this variant increased fibronectin's ability to bind to integrin, thereby maintaining podocyte adhesion. Also, we hypothesised that TBMN arose as the fibronectin variant exhibited a decreased capacity to bind COL4A3/4. Our study is the first to identify and link this novel pathogenic mutation (c.3415G>A) in FN1 to GFND as well as TBMN, which may broaden the phenotype and mutation spectrums of the FN1 gene. We believe our data will positively impact genetic counselling and prenatal diagnostics for GFND with TBMN and other associated conditions that may be commonly benign conditions in humans, and may not require proteinuria-lowering treatments or renal biopsy.
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Affiliation(s)
- Jiawen Qiu
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Huan Chi
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Chun Gan
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Xindi Zhou
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Dan Chen
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Qing Yang
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Yaxi Chen
- Centre for Lipid Research and Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Mo Wang
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Haiping Yang
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Wei Jiang
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China.
| | - Qiu Li
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China.
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50
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Isaranuwatchai S, Chanakul A, Ittiwut C, Ittiwut R, Srichomthong C, Shotelersuk V, Suphapeetiporn K, Praditpornsilpa K. Pathogenic variant detection rate by whole exome sequencing in Thai patients with biopsy-proven focal segmental glomerulosclerosis. Sci Rep 2023; 13:805. [PMID: 36646731 PMCID: PMC9842604 DOI: 10.1038/s41598-022-26291-y] [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: 07/22/2022] [Accepted: 12/13/2022] [Indexed: 01/17/2023] Open
Abstract
The spectra of underlying genetic variants for various clinical entities including focal segmental glomerulosclerosis (FSGS) vary among different populations. Here we described the clinical and genetic characteristics of biopsy-proven FSGS patients in Thailand. Patients with FSGS pathology, without secondary causes, were included in our study. Clinical laboratory and pathological data were collected. Whole-exome sequencing (WES) was subsequently performed. 53 unrelated FSGS patients were recruited. 35 patients were adults (66.0%), and 51 patients were sporadic cases (96.2%). Clinical diagnosis before kidney biopsy was steroid-resistant nephrotic syndrome (SRNS) in 58.5%, and proteinuric chronic kidney disease in 32.1%. Using WES, disease-associated pathogenic/likely pathogenic (P/LP) variants could be identified in six patients including the two familial cases, making the P/LP detection rate of 11.3% (6/53). Of these six patients, two patients harbored novel variants with one in the COL4A4 gene and one in the MAFB gene. Four other patients carried previously reported variants in the CLCN5, LMX1B, and COL4A4 genes. Four of these patients (4/6) received immunosuppressive medications as a treatment for primary FSGS before genetic diagnosis. All four did not respond to the medications, emphasizing the importance of genetic testing to avoid unnecessary treatment. Notably, the mutation detection rates in adult and pediatric patients were almost identical, at 11.4% and 11.1%, respectively. In conclusion, the overall P/LP variant detection rate by WES in biopsy-proven FSGS patients was 11.3%. The most identified variants were in COL4A4. In addition, three novel variants associated with FSGS were detected.
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Affiliation(s)
- Suramath Isaranuwatchai
- Division of Nephrology, Department of Internal Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Division of Nephrology, Department of Internal Medicine, Chulabhorn Hospital, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Ankanee Chanakul
- Division of Nephrology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Chupong Ittiwut
- Division of Medical Genetics and Metabolism, Department of Pediatrics, Center of Excellence for Medical Genomics, Medical Genomics Cluster, Faculty of Medicine, Chulalongkorn University, Bangkok, 10330, Thailand.,Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand
| | - Rungnapa Ittiwut
- Division of Medical Genetics and Metabolism, Department of Pediatrics, Center of Excellence for Medical Genomics, Medical Genomics Cluster, Faculty of Medicine, Chulalongkorn University, Bangkok, 10330, Thailand.,Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand
| | - Chalurmpon Srichomthong
- Division of Medical Genetics and Metabolism, Department of Pediatrics, Center of Excellence for Medical Genomics, Medical Genomics Cluster, Faculty of Medicine, Chulalongkorn University, Bangkok, 10330, Thailand.,Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand
| | - Vorasuk Shotelersuk
- Division of Medical Genetics and Metabolism, Department of Pediatrics, Center of Excellence for Medical Genomics, Medical Genomics Cluster, Faculty of Medicine, Chulalongkorn University, Bangkok, 10330, Thailand.,Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand
| | - Kanya Suphapeetiporn
- Division of Medical Genetics and Metabolism, Department of Pediatrics, Center of Excellence for Medical Genomics, Medical Genomics Cluster, Faculty of Medicine, Chulalongkorn University, Bangkok, 10330, Thailand. .,Excellence Center for Genomics and Precision Medicine, King Chulalongkorn Memorial Hospital, the Thai Red Cross Society, Bangkok, Thailand.
| | - Kearkiat Praditpornsilpa
- Division of Nephrology, Department of Internal Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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