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Christodoulaki V, Kosma K, Marinakis NM, Tilemis FN, Stergiou N, Kampouraki A, Kapogiannis C, Karava V, Mitsioni A, Mila M, Kanaka-Gantenbein C, Makrythanasis P, Tzetis M, Traeger-Synodinos J. Alport Syndrome: Clinical Utility of Early Genetic Diagnosis in Children. Genes (Basel) 2024; 15:1016. [PMID: 39202375 PMCID: PMC11353900 DOI: 10.3390/genes15081016] [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: 07/08/2024] [Revised: 07/30/2024] [Accepted: 07/30/2024] [Indexed: 09/03/2024] Open
Abstract
Alport syndrome (AS) is a hereditary glomerulopathy due to pathogenic variants in COL4A3, COL4A4, and COL4A5. Treatment with Renin-Angiotensin-Aldosterone System (RAAS) inhibitors can delay progression to end stage renal disease (ESRD). From 2018 until today, we performed Whole Exome Sequencing (WES) in 19 patients with AS phenotype with or without positive family history. Fourteen of these patients were children. Genetic testing was extended to family members at risk. All patients received a genetic diagnosis of AS: five X-linked AS (XLAS) males, five X-linked AS (XLAS) females, six autosomal dominant AS (ADAS), and one autosomal recessive AS (ARAS). After cascade screening four XLAS males and eight XLAS females, six ADAS and three ARAS heterozygotes were added to our initial results. Fifteen patients were eligible to start treatment with RAAS inhibitors after their diagnosis. All XLAS female patients, ARAS heterozygotes, and ADAS have been advised to be followed up, so that therapeutic intervention can begin in the presence of microalbuminuria. Genetic diagnosis of AS ensures early therapeutic intervention and appropriate follow up to delay progression to chronic kidney disease, especially in thet pediatric population.
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Affiliation(s)
- Vasileia Christodoulaki
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens (NKUA), 11527 Athens, Greece; (K.K.); (N.M.M.); (F.-N.T.); (A.K.); (P.M.); (M.T.); (J.T.-S.)
- First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, “Aghia Sophia” Children’s Hospital, 11527 Athens, Greece; (N.S.); (C.K.); (V.K.); (C.K.-G.)
| | - Konstantina Kosma
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens (NKUA), 11527 Athens, Greece; (K.K.); (N.M.M.); (F.-N.T.); (A.K.); (P.M.); (M.T.); (J.T.-S.)
| | - Nikolaos M. Marinakis
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens (NKUA), 11527 Athens, Greece; (K.K.); (N.M.M.); (F.-N.T.); (A.K.); (P.M.); (M.T.); (J.T.-S.)
- University Research Institute for the Study and Treatment of Genetic and Malignant Disorders in Childhood, Aghia Sophia Children’s Hospital, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Faidon-Nikolaos Tilemis
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens (NKUA), 11527 Athens, Greece; (K.K.); (N.M.M.); (F.-N.T.); (A.K.); (P.M.); (M.T.); (J.T.-S.)
| | - Nikolaos Stergiou
- First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, “Aghia Sophia” Children’s Hospital, 11527 Athens, Greece; (N.S.); (C.K.); (V.K.); (C.K.-G.)
| | - Afroditi Kampouraki
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens (NKUA), 11527 Athens, Greece; (K.K.); (N.M.M.); (F.-N.T.); (A.K.); (P.M.); (M.T.); (J.T.-S.)
| | - Charalampos Kapogiannis
- First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, “Aghia Sophia” Children’s Hospital, 11527 Athens, Greece; (N.S.); (C.K.); (V.K.); (C.K.-G.)
| | - Vasiliki Karava
- First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, “Aghia Sophia” Children’s Hospital, 11527 Athens, Greece; (N.S.); (C.K.); (V.K.); (C.K.-G.)
| | - Andromachi Mitsioni
- Department of Nephrology, “P. and A. Kyriakou” Children’s Hospital, 11527 Athens, Greece; (A.M.); (M.M.)
| | - Maria Mila
- Department of Nephrology, “P. and A. Kyriakou” Children’s Hospital, 11527 Athens, Greece; (A.M.); (M.M.)
| | - Christina Kanaka-Gantenbein
- First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, “Aghia Sophia” Children’s Hospital, 11527 Athens, Greece; (N.S.); (C.K.); (V.K.); (C.K.-G.)
- Division of Endocrinology, Diabetes and Metabolism, First Department of Pediatrics, Medical School, Aghia Sophia Children’s Hospital, National and Kapodistrian University of Athens, 11527 Athens, Greece
| | - Periklis Makrythanasis
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens (NKUA), 11527 Athens, Greece; (K.K.); (N.M.M.); (F.-N.T.); (A.K.); (P.M.); (M.T.); (J.T.-S.)
| | - Maria Tzetis
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens (NKUA), 11527 Athens, Greece; (K.K.); (N.M.M.); (F.-N.T.); (A.K.); (P.M.); (M.T.); (J.T.-S.)
| | - Joanne Traeger-Synodinos
- Laboratory of Medical Genetics, Medical School, National and Kapodistrian University of Athens (NKUA), 11527 Athens, Greece; (K.K.); (N.M.M.); (F.-N.T.); (A.K.); (P.M.); (M.T.); (J.T.-S.)
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Schott C, Colaiacovo S, Baker C, Weir MA, Connaughton DM. Reclassification of Genetic Testing Results: A Case Report Demonstrating the Need for Structured Re-Evaluation of Genetic Findings. Can J Kidney Health Dis 2024; 11:20543581241242562. [PMID: 38623282 PMCID: PMC11017705 DOI: 10.1177/20543581241242562] [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: 08/16/2023] [Accepted: 03/01/2024] [Indexed: 04/17/2024] Open
Abstract
Rationale Alport Syndrome (AS) is a progressive genetic condition characterized by chronic kidney disease (CKD), hearing loss, and eye abnormalities. It is caused by mutations in the genes COL4A3, COL4A4, and COL4A5. Heterozygous mutations in COL4A4 and COL4A3 cause autosomal dominant Alport Syndrome (ADAS), and a spectrum of phenotypes ranging from asymptomatic hematuria to CKD, with variable extra-renal features. In the past, heterozygous mutations in these genes were thought to be benign, however recent studies show that about 30% of patients can progress to CKD, and 15% can progress to end stage kidney disease (ESKD). Presenting Concerns We present a case of a woman who was noted to have microscopic hematuria pre-living kidney donation. Genetic testing revealed a heterozygous variant of uncertain significance (VUS) in the COL4A4 gene. VUSs are medically nonactionable findings and data show that VUSs can be detected in 41% of all patients who undergo clinical genetic testing. VUSs frustrate clinicians and patients alike. Although they cannot be used in medical decision-making, data suggest that reanalysis can result in the reclassification of a VUS over time. Diagnosis Post-donation, the index patient had a higher than anticipated rise in serum creatinine, raising a concern for possible intrinsic kidney disease. Kidney biopsy was deemed high risk in the setting of a unilateral kidney thereby limiting possible diagnostic intervention to determine the cause of disease. Intervention Re-evaluation of prior genetic testing results and reassessment of the previously identified VUS in COL4A4 was performed 5-years post-donation. These analyses, along with the addition of new phenotypic data and extended pedigree data, resulted in the reclassification of the previously identified VUS to a likely pathogenic variant. Outcomes This case demonstrates the importance of structured, periodic re-evaluation of genetic testing results. With the ever-changing landscape of genetics in medicine, the interpretation of a VUS can be dynamic and therefore warrant caution in living kidney donor evaluations. Studies have shown that about 10% of VUSs can be upgraded to a pathogenic classification after an 18- to 36-month interval. Structured re-evaluation of genomic testing results has not yet been integrated into clinical practice and poses a unique challenge in living kidney donation. Novel findings This case report highlights the variability of the ADAS phenotype caused by pathogenic heterozygous variants in the type 4 collagen genes. It supports the nomenclature change from a benign hematuria phenotype to ADAS, particularly when additional risk factors such as proteinuria, focal segmental glomerulosclerosis or glomerular basement membrane changes on kidney biopsy are present, or as in this case, evidence of disease in other family members.
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Affiliation(s)
- Clara Schott
- Department of Biochemistry, Schulich School of Medicine & Dentistry, University of Western, London, ON, Canada
| | - Samantha Colaiacovo
- Division of Medical Genetics, Department of Pediatrics, Victoria Hospital, London Health Science Center, ON, Canada
| | - Cadence Baker
- Division of Nephrology, Department of Medicine, University Hospital, London Health Sciences Centre, ON, Canada
| | - Matthew A. Weir
- Department of Biochemistry, Schulich School of Medicine & Dentistry, University of Western, London, ON, Canada
- Department of Epidemiology and Biostatistics, Schulich School of Medicine & Dentistry, University of Western, London, ON, Canada
| | - Dervla M. Connaughton
- Department of Biochemistry, Schulich School of Medicine & Dentistry, University of Western, London, ON, Canada
- Division of Nephrology, Department of Medicine, University Hospital, London Health Sciences Centre, ON, Canada
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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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Naylor RW, Lemarie E, Jackson-Crawford A, Davenport JB, Mironov A, Lowe M, Lennon R. A novel nanoluciferase transgenic reporter measures proteinuria in zebrafish. Kidney Int 2022; 102:815-827. [PMID: 35716957 DOI: 10.1101/2021.07.19.452884] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 04/25/2022] [Accepted: 05/09/2022] [Indexed: 05/28/2023]
Abstract
The zebrafish is an important animal system for modeling human diseases. This includes kidney dysfunction as the embryonic kidney (pronephros) shares considerable molecular and morphological homology with the human nephron. A key clinical indicator of kidney disease is proteinuria, but a high-throughput readout of proteinuria in the zebrafish is currently lacking. To remedy this, we used the Tol2 transposon system to generate a transgenic zebrafish line that uses the fabp10a liver-specific promoter to over-express a nanoluciferase molecule fused with the D3 domain of Receptor-Associated Protein (a type of molecular chaperone) which we term NL-D3. Using a luminometer, we quantified proteinuria in NL-D3 zebrafish larvae by measuring the intensity of luminescence in the embryo medium. In the healthy state, NL-D3 is not excreted, but when embryos were treated with chemicals that affected either proximal tubular reabsorption (cisplatin, gentamicin) or glomerular filtration (angiotensin II, Hanks Balanced Salt Solution, Bovine Serum Albumin), NL-D3 is detected in fish medium. Similarly, depletion of several gene products associated with kidney disease (nphs1, nphs2, lrp2a, ocrl, col4a3, and col4a4) also induced NL-D3 proteinuria. Treating col4a4 depleted zebrafish larvae (a model of Alport syndrome) with captopril reduced proteinuria in this system. Thus, our findings validate the use of the NL-D3 transgenic zebrafish as a robust and quantifiable proteinuria reporter. Hence, given the feasibility of high-throughput assays in zebrafish, this novel reporter will permit screening for drugs that ameliorate proteinuria, thereby prioritizing candidates for further translational studies.
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Affiliation(s)
- Richard W Naylor
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Emmanuel Lemarie
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine, and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | | | - J Bernard Davenport
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Aleksandr Mironov
- EM Core Facility (RRID: SCR_021147), Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Martin Lowe
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine, and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.
| | - Rachel Lennon
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK; Department of Paediatric Nephrology, Royal Manchester Children's Hospital, Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK.
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Naylor RW, Lemarie E, Jackson-Crawford A, Davenport JB, Mironov A, Lowe M, Lennon R. A novel nanoluciferase transgenic reporter measures proteinuria in zebrafish. Kidney Int 2022; 102:815-827. [PMID: 35716957 PMCID: PMC7614274 DOI: 10.1016/j.kint.2022.05.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 04/25/2022] [Accepted: 05/09/2022] [Indexed: 11/21/2022]
Abstract
The zebrafish is an important animal system for modeling human diseases. This includes kidney dysfunction as the embryonic kidney (pronephros) shares considerable molecular and morphological homology with the human nephron. A key clinical indicator of kidney disease is proteinuria, but a high-throughput readout of proteinuria in the zebrafish is currently lacking. To remedy this, we used the Tol2 transposon system to generate a transgenic zebrafish line that uses the fabp10a liver-specific promoter to over-express a nanoluciferase molecule fused with the D3 domain of Receptor-Associated Protein (a type of molecular chaperone) which we term NL-D3. Using a luminometer, we quantified proteinuria in NL-D3 zebrafish larvae by measuring the intensity of luminescence in the embryo medium. In the healthy state, NL-D3 is not excreted, but when embryos were treated with chemicals that affected either proximal tubular reabsorption (cisplatin, gentamicin) or glomerular filtration (angiotensin II, Hanks Balanced Salt Solution, Bovine Serum Albumin), NL-D3 is detected in fish medium. Similarly, depletion of several gene products associated with kidney disease (nphs1, nphs2, lrp2a, ocrl, col4a3, and col4a4) also induced NL-D3 proteinuria. Treating col4a4 depleted zebrafish larvae (a model of Alport syndrome) with captopril reduced proteinuria in this system. Thus, our findings validate the use of the NL-D3 transgenic zebrafish as a robust and quantifiable proteinuria reporter. Hence, given the feasibility of high-throughput assays in zebrafish, this novel reporter will permit screening for drugs that ameliorate proteinuria, thereby prioritizing candidates for further translational studies.
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Affiliation(s)
- Richard W Naylor
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Emmanuel Lemarie
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine, and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | | | - J Bernard Davenport
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Aleksandr Mironov
- EM Core Facility (RRID: SCR_021147), Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Martin Lowe
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine, and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.
| | - Rachel Lennon
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK; Department of Paediatric Nephrology, Royal Manchester Children's Hospital, Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK.
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