RESUMO
Hyperhomocysteinemia is a rare autosomal recessive inherited metabolic disorder. The main clinical manifestations of hyperhomocysteinemia include mental retardation, psychological disturbance, thromboembolic events and skeletal abnormalities. The case reported here is of a 28 year-old man admitted in hospital with recurrent seizures. In the brain MRI, areas of venous infarction were seen and MRA revealed thrombosis in brain venous sinuses. Lab investigation showed increases in serum level of homocystein and protein C deficiency. The patient had no family history of genetic disease or cerebrovascular attack. As sinus thrombosis is a multifactorial disease, Protein C deficiency can be one of aggravating causes of thromboembolic events in patients with hyperhomocysteinemia