Two studies each reporting different stroke sub types (Cerebral Venous Thrombosis (CVT) and arterial paediatric ischemic stroke) were found for genes MTRR G66A [42], [43], MTR A2756G [42], [43], MTHFR A1298C [42], [43] and FVL A4070G [36], [42], [43], and therefore ORs for risk were not estimable. This evidence concerns the gene MTRR and Stroke.