Monogenic nephrotic syndrome in Nigerian Children
drome (NS) in African children is unknown despite evidence pointing to racial differences in the prevalence and clinical course of NS. The objective was to determine the frequency of single gene mutations in Nigerian children with idiopathic NS. Methods: Genomic DNA from 89 children with NS from 89 families was screened for mutations in 40 NS genes by targeted sequencing of custom amplicons (TSCA) followed by confirmatory direct sequencing. Both strands of the exons were sequenced and the sequences were analysed with the Sequencher Program. We defined pathogenicity using the American College of Medical Genetics variant classification schema. Nephrotic syndrome and response to corticosteroid were defined using the KDIGO guidelines. Results: The study involved 89 (males: 66.3%) children with NS including 11 (12.5%) children with steroid resistant NS. The median age at diagnosis of NS and enrolment in the study was 5.0 (1.3-14.8) and 8.0 (2.1-16.0) years, respectively. We identified pathogenic mutations in two genes (INF2 and TRPC6) in 2 of 89 (2.2%) children with NS. Interestingly, both children have steroid sensitive (SSNS) course. Conclusions: We found single gene mutations in <5% of Nigerian children with NS and highlight the rarity of commonly described NS genes in Nigerian children. There is need for larger multi-site studies to verify the results of this study.