A case of ADTKD-UMOD presenting with focal segmental glomerulosclerosis in a young male with a positive family history.

Focal segmental glomerulosclerosis (FSGS) is a pathological lesion with diverse etiologies. UMOD gene variants, typically associated with autosomal dominant tubulointerstitial kidney disease (ADTKD), are rarely reported as a cause of FSGS and remain poorly characterized. We report a young male patient with familial nephropathy whose renal biopsy revealed FSGS and whole-exome sequencing identified a heterozygous UMOD variant (OMIM: 191845), c.113 A > T (p.Asn38Ile). This case indicates that UMOD variants can manifest with FSGS as the predominant histological finding, and the accumulation of mutant uromodulin may initiate tubular injury and ultimately leading to secondary glomerulosclerosis. These findings highlight the necessity of incorporating genetic testing into FSGS evaluation to achieve precise diagnosis and guide management.