A new form of digenic non-Mendelian inheritance of Alport syndrome, with coexisting mutations in COL4A3, COL4A4, or COL4A5 genes, has recently been described, simulating autosomal recessive inheritance (digenic mutations in trans) or autosomal dominant inheritance (mutations in in cis mode) [12]. The gene discussed is COL4A4; the disease is Alport syndrome.