Col4a2 mutation causing recurrent intracerebral hemorrhage — /INS;Importance of screening both Col4a1 and Col4a2 in ICH of unknown origin

Background: Type IV collagen α1 and α2 chains form heterotrimers that constitute an essential component of basement membranes including those of the cerebral vasculature. Mutations in COL4A1, encoding the α1 chain, cause a large spectrum of clinical manifestations, including porencephaly, bleeding prone cerebral small vessel disease, intracranial aneurysms and variable systemic abnormalities. Mutations in COL4A2 have recently been reported in a few porencephaly families.