Stroke in early childhood due to homocystinuria.

A previously healthy girl, age 3 years 9 months, presented with right-sided hemiparesis and seizures. Ischemic infarction was confirmed through magnetic resonance imaging and magnetic resonance angiography. Extensive evaluation to discover the underlying etiologies and risk factors predisposing this patient to stroke included coagulation defects, cardiac anomalies, congenital inborn metabolism deficiency, and infections and trauma. Based on the clinical and laboratory results, a diagnosis of homocystinuria was made. Homocystinuria is an inherited disorder that affects the metabolism of the amino acid methionine. Although homocystinuria is usually associated with ischemic strokes, the sudden onset of stroke as the initial clinical presentation of homocystinuria is very rare in early childhood. Based on this case, however, metabolic screening for hyperhomocystinemia is recommended in any child presenting with a stroke.