COL4A1 and CARASIL: Some of these include cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), retinal vasculopathy with cerebral leukodystrophies (RVCL), and collagen type IV, alpha 1 (COL4A1) and alpha 2 (COL4A2)‐related disorders.