Atypical features in MECP2 P152R-associated Rett syndrome.

Background: Rett syndrome is a neurodevelopmental disorder that occurs in individuals with a mutation in the X-linked methyl-CpG-binding protein 2 (2MECP2) gene. 2MECP2 mutations produce a high degree of variability in the clinical phenotypes including the classic Rett features of head growth deceleration, psychomotor regression, deviant communicative ability, hand stereotypes, autonomic dysfunction, and seizures. Atypical forms of Rett such as those with preserved speech do not follow these characteristics.