Methyl-CpG-binding protein 2 (MeCP2) is one of the proteins associated with epigenetic regulation, and mutations of this gene have been identified in the majority of patients with a severe neurodevelopmental disorder, Rett syndrome (RTT), characterized by seizures, ataxic gait, language dysfunction, and autistic behavior [1,2]. Here, MECP2 is linked to atypical Rett syndrome.