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Chen S, Zhang Y, He J, Yang D. Case report: A novel compound heterozygous variant in the COL4A3 gene was identified in a patient with autosomal recessive Alport syndrome. Front Genet 2024; 15:1426806. [PMID: 39071776 PMCID: PMC11272558 DOI: 10.3389/fgene.2024.1426806] [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: 05/02/2024] [Accepted: 06/21/2024] [Indexed: 07/30/2024] Open
Abstract
Alport syndrome (AS), a hereditary kidney disease with a high risk for renal failure, is attributed to pathogenic variants in genes COL4A3, COL4A4, and COL4A5 that encode type IV collagen. Next-generation sequencing (NGS) is increasingly applied to the diagnosis of AS, but complex genotype-phenotype correlation, that is, identifying the significance of variants, is still a huge clinical challenge. In this study, we reported the case of a 27-year-old Chinese woman with a family history of hematuria and proteinuria. Notably, the proband is the only one in her family with renal insufficiency. NGS was performed in this family, and it was revealed that the proband was a compound heterozygote for two variants in the COL4A3 gene: c.2990G>A inherited from her father and c.4981C>T inherited from her mother. We modeled the spatial structure of the corresponding protein and assumed that structural abnormalities led to the breakdown of type IV collagen networks, a major component of the glomerular basement membrane. Thus, the proband was diagnosed with autosomal recessive AS, characterized by severe defects of the glomerular basement membrane. Hence, the proband showed a loss of renal function. This case presentation emphasizes the importance of NGS for AS diagnosis and introduces a novel genotype of AS.
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Affiliation(s)
- Sha Chen
- Department of Nephrology, Tianjin Hospital, Tianjin University, Tianjin, China
| | - Yufeng Zhang
- Department of Nephrology, Tianjin Hospital, Tianjin University, Tianjin, China
| | - Jinjin He
- Clinical College of Orthopedics, Tianjin Medical University, Tianjin, China
| | - Dingwei Yang
- Department of Nephrology, Tianjin Hospital, Tianjin University, Tianjin, China
- Clinical College of Orthopedics, Tianjin Medical University, Tianjin, China
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Uedono H, Mori K, Nakatani S, Watanabe K, Nakaya R, Morioka F, Sone K, Ono C, Hotta J, Tsuda A, Morisada N, Seto T, Nozu K, Emoto M. Novel Digenic Variants in COL4A4 and COL4A5 Causing X-Linked Alport Syndrome: A Case Report. Case Rep Nephrol Dial 2024; 14:1-9. [PMID: 38179179 PMCID: PMC10764090 DOI: 10.1159/000535493] [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: 04/20/2023] [Accepted: 11/18/2023] [Indexed: 01/06/2024] Open
Abstract
Introduction Alport syndrome (AS) is a hereditary, progressive kidney disease characterized by structural abnormalities and dysfunction of the glomerular basement membrane (GBM). AS is classified as X-linked, autosomal, and digenic. The number of cases of digenic AS has increased, but the genotype-phenotype correlation of patient with digenic AS is still unclear. Here, we present a case of digenic AS with novel digenic missense variants in COL4A4 (c.827G>C, p.Gly276Ala) and COL4A5 (c.4369G>C, p.Gly1457Arg). Case Presentation The patient was a 29-year-old Japanese man suffering from persistent microscopic hematuria and proteinuria without kidney function impairment. Kidney biopsy showed focal interstitial foam cell infiltration, global and segmental glomerulosclerosis. Immunofluorescence staining for collagen IV α5 was almost negative in the GBM and Bowman's capsule. Electron microscopy revealed irregular thickening with lamellation and segmental thinning of the GBM. Clinical and pathological findings were consistent with AS. Comprehensive next-generation sequencing revealed a heterozygous missense variant in COL4A4 (c.827G>C, p.Gly276Ala) in exon 1 and a hemizygous missense variant in COL4A5 (c.4369G>C, p.Gly1457Arg) in exon 49 on the patient's paternal and maternal alleles, respectively. The same digenic variants were detected in his sister, and she also showed a similar phenotype. After treatment with angiotensin-converting enzyme inhibitors, proteinuria decreased from 2.3 to 1.1 g/g creatinine, but occult blood persisted. During follow-up, kidney function has been preserved. Conclusion The novel genotype of our case provides more information on the genotype-phenotype correlation of digenic XLAS, although long-term follow-up is required. The findings in the present case also indicate the importance of genetic tests for family members of a patient diagnosed with digenic AS.
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Affiliation(s)
- Hideki Uedono
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Katsuhito Mori
- Department of Nephrology, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Shinya Nakatani
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Kohei Watanabe
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Rino Nakaya
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Fumiyuki Morioka
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Kazuma Sone
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Chie Ono
- Department of Medical Genetics, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Junko Hotta
- Department of Medical Genetics, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Akihiro Tsuda
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Toshiyuki Seto
- Department of Medical Genetics, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masanori Emoto
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
- Department of Nephrology, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
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Zhu F, Li Y, Wang Y, Yao Y, Zeng R. The same heterozygous Col4A4 mutation triggered different renal pathological changes in Chinese family members. Front Genet 2023; 14:1180149. [PMID: 37323683 PMCID: PMC10265269 DOI: 10.3389/fgene.2023.1180149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/18/2023] [Indexed: 06/17/2023] Open
Abstract
Background: Mutations in the collagen components of the glomerular basement membrane (GBM) often lead to hereditary glomerulonephritis. Previous studies have identified that autosomal dominant mutations of Col4A3, Col4A4 or Col4A5 are associated with thin basement membrane nephropathy (TBMN), Alport syndrome and other hereditary kidney diseases. However, the genetic mutations underlying other glomerulonephritis types have not been elucidated. Methods: In this study, we investigated a Chinese family with hereditary nephritis using the methods of genetic sequencing and renal biopsy. Genomic DNA was extracted from peripheral blood of the proband and her sister, and subsequently was performed genetic sequencing. They were found to have the similar mutation sites. Other family members were then validated using Sanger sequencing. The proband and her sister underwent renal puncture biopsies, and experienced pathologists performed PAS, Masson, immunofluorescence, and immunoelectron microscopic staining of the kidney tissue sections. Results: Through genetic sequencing analysis, we detected a novel heterozygous frameshift mutation c.1826delC in the COL4A4 (NM_000092.4) gene coding region, and 1 hybrid missense variation c.86G>A (p. R29Q) was also detected in the TNXB (NM_019105.6) gene coding region in several members of this Chinese family. Interestingly, we found that the same mutations caused different clinical features and distinct pathological changes in individual family members, which confirmed that pathological and genetic testing are crucial for the diagnosis and treatment of hereditary kidney diseases. Conclusion: In this study, we found a novel heterozygous mutation in Col4A4 and co-mutations of the TNXB gene in this Chinese family. Our study indicated that the same Col4A4 mutated variants produced different pathological and clinical changes in different family members. This discovery may provide novel insights into the study of hereditary kidney disease. In addition, new genetic biology techniques and renal biopsy of individual family members are essential.
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Affiliation(s)
- Fengming Zhu
- Department of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yueqiang Li
- Department of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuxi Wang
- Department of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ying Yao
- Department of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Nutrition, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rui Zeng
- Department of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, China
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Prasad B, Sharma A, Lanktree MB, Goyal K, Dokouhaki P. Kidney Biopsy and Type IV Collagen Gene Sequencing Fail to Explain Hematuria in Loin Pain Hematuria Syndrome. Kidney Int Rep 2023; 8:1013-1021. [PMID: 37180518 PMCID: PMC10166728 DOI: 10.1016/j.ekir.2023.02.1075] [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: 11/08/2022] [Revised: 02/06/2023] [Accepted: 02/13/2023] [Indexed: 02/24/2023] Open
Abstract
Introduction Loin pain hematuria syndrome (LPHS) is a rare clinical syndrome with a reported prevalence of 1 in 10,000. The syndrome is characterized by severe pain localized to the kidney in the absence of identifiable urinary tract disease. Because of an inadequate understanding of the pathophysiology of the disease, the goal of management has been limited to symptomatic pain management. Through detailed phenotype and genotype assessment we sought to identify possible underlying etiologies. Methods We completed a chart review, ultrasound imaging, kidney biopsy, and type IV collagen (COL4A3, COL4A4, and COL4A5) gene sequencing in 14 patients with loin pain hematuria recruited from a single center. Results Red blood cells and red cell casts were observed within the tubules in 10 of 14 patients. The glomerular basement membrane (GBM) was normal in 11 patients and thickened in 1 patient. Staining for IgA kappa was present in 1 patient. C3 deposition without any inflammation was present in 7 patients. Arteriolar hyalinosis was present in 4 patients and endothelial cell injury was present in 6 patients. No pathogenic COL4A3, COL4A4, or COL4A5 variants were identified. Conclusion Conventional histopathology and genetic testing for type IV collagen variants failed to identify the cause of hematuria in 14 patients with LPHS.
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Affiliation(s)
- Bhanu Prasad
- Section of Nephrology, Department of Medicine, Regina General Hospital, Regina, Saskatchewan, Canada
- College of Medicine, University of Saskatchewan, Regina, Saskatchewan, Canada
| | - Aditi Sharma
- Institute for Microbial Systems and Society, University of Regina, Regina, Saskatchewan, Canada
| | - Mathew B Lanktree
- Division of Nephrology, St. Joseph’s Healthcare Hamilton, McMaster University, Hamilton, Ontario, Canada
| | - Kunal Goyal
- Department of Radiology, Regina General Hospital, Regina, Saskatchewan, Canada
| | - Pouneh Dokouhaki
- Department of Pathology and Laboratory Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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