Basilar artery thrombosis in a child heterozygous for factor V Leiden mutation.

Activated protein C resistance, usually because of factor V Leiden mutation, is considered to be the most common hereditary prothrombotic condition. A 9-year-old male with a basilar artery stroke and activated protein C resistance is described. The patient, found to be heterozygous for factor V Leiden mutation, is one of several recent reports that suggest that activated protein C resistance is an important risk factor for spontaneous arterial thrombosis in infancy and childhood.