They were Moyamoya disease (MMD), COL4A1, COL4A2 mutations, Ehlers–Danlos syndrome (E-D), neurofibromatosis type 1 (Nf1), sickle cell disease (SCD), cerebral cavernous malformations (CCM), hereditary hemorrhagic telangiectasia (HHT) and Marfan syndrome. This evidence concerns the gene COL4A2 and sickle cell disease.