Although over 1000 mutations have been characterized along the entire length of the gene, including nonsense, missense, frameshift, and large truncation mutations (Amir and Zoghbi, 2000; Weaving et al., 2005; Philippe et al., 2006; Cuddapah et al., 2014), 65% of RTT cases are caused by eight common missense mutations in the region that encodes the methyl-CpG binding domain (MDB) of MeCP2 (Miltenberger-Miltenyi and Laccone, 2003). Here, MECP2 is linked to Rett syndrome.