Abdominal aortic aneurysm in homocystinuria.

The first reported case of abdominal aortic aneurysm complicating homocystinuria is presented. The clinical features and microscopic findings were identical to those of an atherosclerotic aneurysm. Homocystinuria may stimulate Marfan's syndrome but can be differentiated by the cyanide-nitroprusside screening test for homocystine in urine. Although homocystinuria is accompanied by an increased risk of thrombosis, surgical treatment of complicating diseases should not be avoided. Pyridoxine treatment is recommended.