Hyperhomocysteinemia and arterial aneurysm.

Hyperhomocysteinemia (HCY) is an independent risk factor for atherosclerosis. Arterial aneurysm has rarely been described in association with heterozygous HCY. Here we report two cases of this association. Case 1 was 32-Year-old man who presented with distal trophic manifestations of the lower extremities. Upon investigation, occlusive arterial disease with fusiform aneurysm of both popliteal arteries and occlusion of the left cubital artery were found. Laboratory findings indicated HCY due to homozygous methylene tetrahydrofolate reductase (MTHFR) deficiency. Case 2 was 38-year-old man with no history of trauma who presented with repeated ischemic events involving the right hand in association with isolated aneurysm of the right cubital artery. Histological study demonstrated extensive dystrophic changes in the aneurysmal vessel wall, including sclerohyalin deposits. The only abnormality was homozygous MTHFR deficiency. Pathologic changes induced by HCY in vessel walls may be implicated in early arterial aneurysm. The association of anatomic lesions, young age, and absence of other causes suggests that the relationship between HCY and arterial aneurysm observed in these two patients was not coincidental.