Whole-exome sequencing in pediatric patients with glomerulonephritis.

Introduction: High-throughput sequencing methods revealed disease-causing and susceptibility genes underlying glomerulonephritis (GN). Genetic disorders mimicking GN may be diagnosed in this way. The aim of this study was to perform whole-exome sequencing (WES) in a cohort of sporadic pediatric patients diagnosed with primary or secondary GN.

Method: Thirty-one patients with GN and 50 nephrologically and immunologically healthy pediatric patients (control group - CG) were genetically analyzed. Allele frequencies were compared with the GnomAD database. WES was performed in the laboratory 3billion in South Korea.

Results: Among 10 patients with primary GN, two patients were positive on WES (20%). One had a likely pathogenic heterozygous variant in the COL4A3 gene associated with Alport syndrome, and one had a heterozygous novel variant of uncertain significance in the CD46 gene associated with atypical hemolytic uremic syndrome (aHUS). In two of 14 patients with systemic lupus erythematosus (SLE) and GN, a heterozygous pathogenic variant (c.841_849 + 19del) in the C2 gene was detected. We found no significant variants in seven patients with Henoch-Schönlein purpura (HSP) and GN.

Conclusion: WES helped us detect hereditary diseases that have a clinical presentation like GN, including Alport syndrome and possible aHUS. Finding susceptibility genes in GN helped us understand disease pathophysiology.