In addition, there were 83 individuals heterozygous for one of these variants, with 70 (84%) heterozygous for p.Gly533Asp in COL4A4 and 13 (16%) for p.Gly139Arg in COL4A3 (Table 1), consistent with the diagnosis of AD AS or thin basement membrane nephropathy. Here, COL4A3 is linked to Alzheimer disease.