A case of familial glomerulopathy with fibronectin deposits caused by the Y973C mutation in fibronectin.

Glomerulopathy with fibronectin deposits is a rare hereditary kidney disease characterized by the extensive deposition of fibronectin in glomeruli, particularly in mesangial regions and subendothelial zones. Prognostically, the disease is known as slowly progressive, leading to kidney failure in most cases. We recently diagnosed glomerulopathy with fibronectin deposits in a 24-year-old man in whom proteinuria was detected incidentally. Genetic analysis of the fibronectin 1 (FN1) gene showed heterozygosity for the Y973C mutation. The same mutation was found in his elder brother, who similarly experienced proteinuria. Both patients had normal kidney function but persistent proteinuria after 30 months and 11 years of follow-up, respectively.