X-linked malformations of cortical development.

Disorders of the development of the human cortex are recognized as significant causes of mental retardation, epilepsy, and congenital neurologic deficits. These malformations may be restricted to the brain or may be one component of a generalized malformation syndrome. Through the efforts of several groups, a large number of human cortical malformations have been identified and classified. Studies of informative families and sporadic patients with specific chromosomal rearrangements or deletions have demonstrated a genetic basis for many of these disorders. Subsequent work has facilitated a precise genetic diagnosis and provided insight into the molecular basis of some of these malformations. This review will discuss four cortical malformation syndromes, which are known or likely to have an X-linked inheritance pattern: bilateral periventricular nodular heterotopia, X-linked lissencephaly/subcortical band heterotopia, X-linked lissencephaly with abnormal genitalia, and X-linked bilateral perisylvian polymicrogyria.