Rett syndrome: clinical update and review of recent genetic advances.

Rett syndrome, a severe neurodevelopmental disorder occurring almost exclusively in females, is thought to be the second most common cause of profound mental retardation in females after Down syndrome. Recent genetic advances suggest the gene for Rett syndrome to be located on the distal arm of the X chromosome, Xq28. This manuscript reviews the clinical phenotype, natural history and current genetic understanding of the disorder.