Homocystinuria presenting with cerebral venous thrombosis: a case report highlighting progressive thrombosis

Homocystinuria is a hereditary metabolic disorder primarily caused by defects in enzymes involved in methionine metabolism, resulting in excessive accumulation of homocysteine and its metabolites in the blood and urine. Cerebral venous sinus thrombosis (CVST), premature atherosclerosis, and other thromboembolic events are among the most serious clinical manifestations of homocystinuria.

We report a 13-year-old boy who initially presented with headache, followed by progressive disturbance of consciousness and status epilepticus. Cranial magnetic resonance imaging (MRI) revealed superior sagittal sinus thrombosis. He was transferred to a tertiary hospital, where he underwent emergency thrombus aspiration under digital subtraction angiography (DSA) guidance and received low-molecular-weight heparin (LMWH) anticoagulation. Although endovascular aspiration combined with LMWH controlled the seizures, his venous thrombosis continued to progress. He subsequently developed lower-extremity deep vein thrombosis, acute pulmonary embolism, and ventricular fibrillation. Clinical biochemical evaluation and genetic testing confirmed classic homocystinuria. Targeted therapy with warfarin, aspirin, vitamin B6, folic acid, and betaine resulted in a favorable prognosis.

Early etiological screening, including genetic testing, should be prioritized in young patients with unexplained or recurrent thrombosis to optimize treatment and prognosis. Rational use of anticoagulants combined with targeted metabolic therapy (vitamin B6, folic acid, betaine) and antiplatelet therapy is critical for improving outcomes in such patients.