Periventricular nodular heterotopia (PVNH) is a developmental brain disorder that causes learning disability and seizures, but one of its most life-threatening complications for these young patients is cardiovascular disease. Joint, pulmonary, and gastrointestinal complications also have been identified. The disorder was first described by the late Peter Huttenlocher, MD, and the causative gene (called Filamin A, FLNA) was identified by Christopher A. Walsh, MD, PhD, of Boston Children’s Hospital.
Affected individuals are usually females, because affected males die before birth or soon after. Prenatal diagnosis by molecular genetic testing is possible if the disease-causing mutation has been identified in an affected relative. The periventricular nodules can be visualized by ultrasound examination as early as 24 weeks of gestation, but the sensitivity of this finding is unknown. But often the disorder presents itself unexpectedly: while half of affected females inherit the gene mutation from their mother, the other half have a new mutation not seen before in the family. For women with X-linked PVNH, the risk of passing the mutation to each child is 50 percent.