Alpo syndrome is noted because of defect in what type of collagen

Alpo syndrome is caused by mutations in COL4A3, COL4A4, and COL4A5, three of six human genes involved in basement membrane (type IV) collagen biosynthesis. ... Basement membranes are thin, sheet-like structures that separate and suppo cells in many tissues. Ref ganong's review of medical physiology 25e p540