Clinical diagnosis of this disorder can be made when one of the following four criteria are met: a) abnormal staining of the α5 (IV) chain in the epidermal basement membrane (EBM); b) abnormal staining of the α (IV) chains in the glomerular basement membrane (GBM); c) mutations in the COL4A3/4/5 genes; and d) ultrastructural changes in the GBM typical of Alport syndrome (Wang et al., 2012; Savige et al., 2013). The gene discussed is COL4A3; the disease is Alport syndrome.