Type IV collagen gene mutations were discovered in 38% of patients with familial FSGS and 3% with sporadic FSGS with more than half of the mutations appearing in COL4A5. The presence of hematuria, hearing loss and GBM abnormalities might indicate the possibility of an underlying COL4 mutation (14). The gene discussed is COL4A5; the disease is focal segmental glomerulosclerosis.