A Case of UMOD-Associated Nephropathy Mimicking Focal Segmental Glomerulosclerosis in a Young Male with a Positive Family History

Focal segmental glomerulosclerosis (FSGS) is a pathological manifestation with diverse causes, but its link to UMOD gene mutations - typically associated with autosomal dominant tubulointerstitial kidney disease (ADTKD) - is rare and not well characterized. We report a young male patient with familial nephropathy in whom renal biopsy showed FSGS and whole-exome sequencing identified compound heterozygous pathogenic variants in UMOD (OMIM: 191845), c.113A > T (p.Asn38Ile). This case indicates that UMOD mutations can present primarily as FSGS on biopsy, and the accumulation of mutant uromodulin may initiate tubular injury and ultimately secondary glomerulosclerosis. These findings highlight the necessity of incorporating genetic testing into FSGS evaluation to achieve precise diagnosis and guide management.