Chromosome X and 17-linked lissencephaly (smooth brain) syndromes

Lissencephaly (smooth brain) is a severe malformation of neuronal migration with a relatively smooth cerebral surface, thick and poorly organized cortex, and clinical signs of severe neurologic dysfunction. Subcortical band heterotopia is part of the lissencephaly malformation spectrum now referred to as the agyriapachygyria-band spectrum. Chromosome 17-linked lissencephaly (patients with Miller-Dieker syndrome) have classical lissencephaly, characteristic facial features, and perhaps other associated birth defects. The critical region for the lissencephaly phenotype has been mapped to 17p13.3, but the identity of the chromosome 17 lissencephaly gene remains unknown. The gene responsible for X-linked lissencephaly has been mapped to Xq22.3. Autosomal recessive classical lissencephaly is thought to exist, although it is considered rare.