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Watanabe A, Guaragna MS, Belangero VMS, Casimiro FMS, Pesquero JB, de Santis Feltran L, Palma LMP, Varela P, de Menezes Neves PDM, Lerario AM, de Souza ML, de Mello MP, de Brito Lutaif ACG, Ferrari CR, Sampson MG, Onuchic LF, Nogueira PCK. APOL1 in an ethnically diverse pediatric population with nephrotic syndrome: implications in focal segmental glomerulosclerosis and other diagnoses. Pediatr Nephrol 2021; 36:2327-2336. [PMID: 33585978 DOI: 10.1007/s00467-021-04960-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/25/2020] [Accepted: 01/20/2021] [Indexed: 11/26/2022]
Abstract
BACKGROUND APOL1 high-risk genotypes (HRG) are associated with increased risk of kidney disease in individuals of African ancestry. We analyzed the effects of APOL1 risk variants on an ethnically diverse Brazilian pediatric nephrotic syndrome (NS) cohort. METHODS Multicenter study including 318 NS patients, categorized as progressors to advanced CKD [estimated glomerular filtration rate (eGFR)] < 30 mL/min/1.73 m2] and slow/non-progressors (eGFR > 30 mL/min/1.73 m2 through the study). We employed Cox regression with progression time as the outcome and APOL1 genotype as the independent variable. We tested this association in the entire cohort and three subgroups; (1) focal segmental glomerulosclerosis (FSGS), (2) steroid-resistant NS (SRNS), and (3) those who underwent kidney biopsy. RESULTS Nineteen patients (6%) had an HRG. Of these, 47% were self-reported White. Patients with HRG manifested NS at older ages and presented higher frequencies of FSGS and SRNS. HRG patients progressed to advanced CKD more often than low-risk-genotype (LRG) children in the whole NS cohort (p = 0.001) and the three subgroups. In SRNS and biopsied patients, a single risk variant was associated with trends of higher CKD progression risk. CONCLUSIONS Novel discoveries include a substantial prevalence of HRG among patients self-reported White, worse kidney outcomes in HRG versus LRG children in the FSGS subgroup, and a trend of higher CKD progression risk associated with a single risk variant in the SRNS cohort. These findings suggest APOL1-associated NS extends beyond patients self-reported non-White, the HRG effect is independent of FSGS, and a single risk variant may have a detrimental impact in children with NS.
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Affiliation(s)
- Andreia Watanabe
- Department of Pediatrics, University of São Paulo School of Medicine, São Paulo, Brazil
- Division of Molecular Medicine, University of São Paulo School of Medicine, São Paulo, Brazil
| | - Mara Sanches Guaragna
- Center for Molecular Biology and Genetic Engineering, State University of Campinas, Campinas, Brazil
| | | | - Fernanda Maria Serafim Casimiro
- Center for Diagnosis and Research on Genetic Diseases, Department of Biophysics, Federal University of São Paulo School of Medicine, São Paulo, Brazil
| | - João Bosco Pesquero
- Center for Diagnosis and Research on Genetic Diseases, Department of Biophysics, Federal University of São Paulo School of Medicine, São Paulo, Brazil
| | | | | | - Patrícia Varela
- Center for Diagnosis and Research on Genetic Diseases, Department of Biophysics, Federal University of São Paulo School of Medicine, São Paulo, Brazil
| | - Precil Diego Miranda de Menezes Neves
- Division of Molecular Medicine, University of São Paulo School of Medicine, São Paulo, Brazil
- Division of Nephrology, University of São Paulo School of Medicine, São Paulo, Brazil
| | | | - Marcela Lopes de Souza
- Center for Molecular Biology and Genetic Engineering, State University of Campinas, Campinas, Brazil
| | | | | | | | - Matthew Gordon Sampson
- Division of Pediatric Nephrology, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- Broad Institute, Cambridge, MA, USA
| | - Luiz Fernando Onuchic
- Division of Molecular Medicine, University of São Paulo School of Medicine, São Paulo, Brazil.
- Division of Nephrology, University of São Paulo School of Medicine, São Paulo, Brazil.
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Guaragna MS, de Brito Lutaif ACG, de Souza ML, Maciel-Guerra AT, Belangero VMS, Guerra-Júnior G, de Mello MP. Promises and pitfalls of whole-exome sequencing exemplified by a nephrotic syndrome family. Mol Genet Genomics 2019; 295:135-142. [PMID: 31520189 DOI: 10.1007/s00438-019-01609-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 09/05/2019] [Indexed: 01/12/2023]
Abstract
High-throughput techniques such as whole-exome sequencing (WES) show promise for the identification of candidate genes that underlie Mendelian diseases such as nephrotic syndrome (NS). These techniques have enabled the identification of a proportion of the approximately 54 genes associated with NS. However, the main pitfall of using WES in clinical and research practice is the identification of multiple variants, which hampers interpretation during downstream analysis. One useful strategy is to evaluate the co-inheritance of rare variants in affected family members. Here, we performed WES of a patient with steroid-resistant NS (SRNS) and intermittent microhematuria. Currently, 15 years after kidney transplantation, this patient presents normal kidney function. The patient was found to be homozygous for a rare MYO1E stop-gain variant, and was heterozygous for rare variants in NS-associated genes, COL4A4, KANK1, LAMB2, ANLN, E2F3, and APOL1. We evaluated the presence or absence of these variants in both parents and 11 siblings, three of whom exhibited a milder phenotype of the kidney disease. Analysis of variant segregation in the family, indicated the MYO1E stop-gain variant as the putative causal variant underlying the kidney disease in the patient and two of her affected sisters. Two secondary variants in COL4A4-identified in some other affected family members-require further functional studies to determine whether they play a role in the development of microhematuria in affected family members. Our data illustrate the difficulties in distinguishing the causal pathogenic variants from incidental findings after WES-based variant analysis, especially in heterogenous genetic conditions, such as NS.
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Affiliation(s)
- Mara Sanches Guaragna
- Laboratory of Human Molecular Genetics, Center for Molecular Biology and Genetic Engineering (CBMEG), State University of Campinas, UNICAMP, Caixa Postal 6010, 13083-875, Campinas, SP, Brazil.
| | - Anna Cristina Gervásio de Brito Lutaif
- Integrated Center of Pediatric Nephrology (CIN), Department of Pediatrics, School of Medical Sciences (FCM), State University of Campinas, UNICAMP, Campinas, Brazil
| | - Marcela Lopes de Souza
- Laboratory of Human Molecular Genetics, Center for Molecular Biology and Genetic Engineering (CBMEG), State University of Campinas, UNICAMP, Caixa Postal 6010, 13083-875, Campinas, SP, Brazil
| | | | - Vera Maria Santoro Belangero
- Integrated Center of Pediatric Nephrology (CIN), Department of Pediatrics, School of Medical Sciences (FCM), State University of Campinas, UNICAMP, Campinas, Brazil.,Department of Pediatrics, School of Medical Sciences (FCM), UNICAMP, Campinas, SP, Brazil
| | - Gil Guerra-Júnior
- Department of Pediatrics, School of Medical Sciences (FCM), UNICAMP, Campinas, SP, Brazil.,Growth and Development Laboratory, Center for Investigation in Pediatrics (CIPED), School of Medical Sciences (FCM), UNICAMP, Campinas, SP, Brazil
| | - Maricilda Palandi de Mello
- Laboratory of Human Molecular Genetics, Center for Molecular Biology and Genetic Engineering (CBMEG), State University of Campinas, UNICAMP, Caixa Postal 6010, 13083-875, Campinas, SP, Brazil
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