Loss-of-function mutations in MeCP2 cause Rett Syndrome while duplications and/or triplications spanning the MeCP2 locus result in progressive neurological disorders characterized by autism, motor abnormalities, and seizures (Ben-Shachar et al., 2009; del Gaudio et al., 2006; Ramocki et al., 2009; Ramocki et al., 2010; Van Esch et al., 2005). The gene discussed is MECP2; the disease is Rett syndrome.