Over the past decade, researchers have uncovered suggestive links between epigenetics and autism, for example, autism is associated with duplications of 15q11-13 (especially maternally inherited), an imprinted region in the genome where DNA methylation status has been linked to Prader-Willi syndrome (PWS) and Angelman syndrome (AS) [66]; mutation within a gene that encodes a methyl-DNA-binding protein (MECP2, (MIM accession no.: 300005)) is the causative agent of Rett syndrome [67]; and mutation of this same gene has been associated with both autism and AS populations [55]. The gene discussed is MECP2; the disease is atypical Rett syndrome.