Rett syndrome is caused by loss of function of the methyl-CpG binding protein 2 (MECP2) and is characterized by an initial period of normal development of about 5 months followed by deceleration of language development, psychomotor retardation, seizures and loss of social engagement skills (Chahrour and Zoghbi, 2007). This evidence concerns the gene MECP2 and atypical Rett syndrome.