Consistent with the shared microangiopathic pathophysiology of lacunar stroke and SVE, 63% of the SVE patients have had, in addition to the above symptoms, lacunar infarctions. SVE patients with and without lacunar infarctions did not significantly differ in regard to homocysteine concentrations (17· 8 [SD 8· 0] vs 18· 6 [9· 6] mol/L, not significant).

Compared with patients without cerebrovascular disease, patients with SVE showed significantly decreased plasma concentrations of vitamin B6 and B12 but not of folate. However, concentrations of vitamin B12 (r=–0· 24, p< 0· 05) and folate (r=–0· 29, p= 0· 01) but not those of vitamin B6 correlated with homocysteine concentrations. This study on a large cohort of patients with SVE and controls demonstrates that homocysteine concentrations are markedly increased in cerebral microangiopathy but not in cerebral macroangiography on which previous studies have focused. 2 This suggests that homocysteine injures the small penetrating cerebral arteries and arterioles rather than larger brain-supplying arteries.