These rare syndromes included cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL, n = 2), primary angiitis of the central nervous system (PACNS, n = 3), one patient with secondary central nervous system vasculitis associated with systemic lupus erythematosus (SLE), one patient with severe anemia and hypovolemia, and one patient with polycytemia vera, heterozygous Factor V Leiden mutation and warfarin below therapeutic level. This evidence concerns the gene F5 and primary central nervous system vasculitis.