COL4A3 and focal segmental glomerulosclerosis: In family 2, a novel COL4A3 missense mutation c.G2290A (p.Gly997Glu) was identified in a 45-year-old male diagnosed with focal segmental glomerulosclerosis and was present in all his affected family members, who exhibited disease ranging from isolated microscopic hematuria to end stage renal disease (ESRD).