Fatal haemorrhagic infarct in an infant with homocystinuria

Thrombotic and thromboembolic complications are the main causes of morbidit y and mortality in patients with homocystinuria. However, it is unusual for thrombosis and infarction to be the presenting feature leading to investig ation for homocystinuria and cerebrovascular lesions in the first year of l ife. We describe a previously healthy 6-month-old infant who presented with a large middle-cerebral-artery territory infarction and died of massive br ain swelling. Homocystinuria due to cystathionine beta-synthase (CBS) defic iency was diagnosed by metabolite analysis and confirmed by enzymatic activ ity measurement in a postmortem liver biopsy, Homocystinuria should be cons idered in the differential diagnosis of venous or arterial thrombosis, rega rdless of age, even in the absence of other common features of the disease. We recommend systematic metabolic screening for hyperhomocysteinemia in an y child presenting with vascular lesions or premature thromboembolism.