Alport syndrome (AS) is a rare genetic disease of the glomerular basement membrane (GBM) caused by mutations in the COL4A3, COL4A4, and COL4A5 genes, with a prevalence ranging from 1 in 5,000 to 1 in 53,000 individuals in different populations (1). The gene discussed is COL4A5; the disease is Alport syndrome.