Bilateral periventricular nodular heterotopia with mental retardation and frontonasal malformation.

Bilateral periventricular nodular heterotopia (BPNH) is a recently recognized malformation of neuronal migration in which nodular masses of gray matter line the walls of the lateral ventricles. Most affected individuals are females with epilepsy and normal intelligence, but no other congenital anomalies. Studies in families with multiple affected individuals, always all females, have mapped one BPNH gene to chromosome Xq28. Several other BPNH syndromes associated with mental retardation and epilepsy but without significant dysmorphic facial features have been observed in males only, which may also be X-linked. This report describes a new syndrome with BPNH.