Three infants with familial factor V Leiden mutation and neonatal cerebrovascular disorders are reported from the Children’s Hospital of Philadelphia, PA. One had placental thrombosis. Activated protein C resistance caused by factor V Leiden mutation is an important cause of in utero ischemic infarction and hemorrhagic stroke and may present with neonatal hemiplegic cerebral palsy. 
COMMENT. Infants with hemiplegic cerebral palsy caused by a vascular accident should be tested for factor V Leiden mutation, especially if a parent has suffered a stroke, venous thrombosis, or heart attack. Factor V Leiden may coexist with hereditary homocystinuria, another prothrombotic disorder.
The role of hyperhomocysteinemia in stroke is emphasized in a study of 125 consecutive adults at the University of Munster, Germany . The prevalence was 20% in all patients with stroke, and impaired cognition was more pronounced in those with hyperhomocysteinemia.