MECP2 and atypical Rett syndrome: For example, Rett syndrome, a neurodevelopmental disorder, is caused by mutations in the gene encoding methyl-CpG-binding protein-2 (MECP2) [8], and alpha-thalassemia/mental retardation X-linked (ATRX) syndrome is caused by mutations in ATRX, which encodes a member of the SWI/SNF family of chromatin remodeling proteins.