MECP2 and atypical Rett syndrome: Altered expression and function of MECP2/Mecp2/MeCP2 have been linked to Rett syndrome (RTT) [2,3,4], MECP2 duplication syndrome (MDS) [5,6,7], autism spectrum disorders (ASD) [8,9], and fetal alcohol spectrum disorders (FASD) [10,11].