The association of the factor V Leiden mutation and cerebrovascular disorder (CVD) in children is reviewed and the clinical features of 8 children with cerebral palsy (CP) and the Leiden mutation are described from the National Institute of Neurological Disorders and Stroke, Bethesda, MD. Since 1995, 120 children with CVD or CP and factor V Leiden mutation have been reported in the literature. Cerebral infarction had occurred in 73 (typically left middle cerebral), cerebral venous thrombosis in 18, intraventricular or intracerebral hemorrhage in 14, CP in 9, and porencephaly in 6. Over half occurred in the perinatal period, and 69% in the first year of life. Seizures followed by acute hemiparesis were the most common neurologic symptoms. Additional exogenous risk factors for CVD in two thirds included birth complications, infection, cardiac disease, or malignancy, and 42% had additional acquired or genetic thrombotic risk factors. Maternal histories included pregnancy-related thrombosis, spontaneous abortion, toxemia, and placental abnormalities. At long-term follow-up, recurring seizures, hemiparesis, and developmental delay were common findings. In the 8 patients with CP followed by the authors, the translational product of the factor V Leiden mutation was elevated at 12-18 mcg/mL in all; protein C, protein S, and antithrombin III levels were also elevated in some; and the placenta was infarcted in 4 of 6 examined. 
COMMENT. Although the risk of stroke in a child born to a mother with factor V Leiden factor is probably low, the incidence of factor V Leiden mutation in children with cerebral palsy or porencephaly is significant. Associated exogenous and endogenous risk factors are also important and deserve further study. Factor V Leiden mutation leads to thrombus formation in the heart, ductus arteriosus, deep veins, or placenta, which then result in emboli to the brain, infarction and stroke. An association with intraventricular hemorrhage and cerebral venous thrombosis is also demonstrated.