Focal segmental glomerulosclerosis associated with undescribed mutation in the LMX1B gene.

A 50-year-old woman presented with nephrotic proteinuria and preserved glomerular filtration rate. A renal biopsy showed focal segmental glomerulosclerosis (FSGS) and glomerular basement membrane thinning. Her brother has a long history of chronic kidney disease, formerly diagnosed with minimal change disease, and eventually received a kidney allograft, developing high-grade proteinuria and decline in kidney function. FSGS was found by biopsy. Lastly, one paternal uncle suffered from the same condition, but he declined a biopsy. A genetic test identified a novel missense mutation in LMX1B, c.349G > A:p(Gly117Ser). Thus, the present series of cases shows a familial LMX1B-associated nephropathy presenting with FSGS.