Col4a1 or Col4a2-Related Cerebral Small Vessel Disease, also known as col4a1 or col4a2-related cerebral angiopathy, is related to col4a1 or col4a2-related cerebral small vessel disease with hemorrhagic tendancy and col4a1 or col4a2-related cerebral small vessel disease with ischemic tendancy. An important gene associated with Col4a1 or Col4a2-Related Cerebral Small Vessel Disease is COL4A1 (Collagen Type IV Alpha 1 Chain).