In 1997, researchers reviewed the clinical spectrum associated with mutations of several chains of type IV collagen.[9] They listed the three mutations that had been identified in the COL4A4 gene: 1 in familial benign hematuria and 2 in AS with the development of renal failure at 14 and 18 years of age, respectively. The gene discussed is COL4A4; the disease is hematuria, benign familial.