The importance of DNA methylation in normal brain function and development is exemplified by the neurodevelopmental deficits associated with mutations in the methyl CpG binding protein 2 gene (MECP2) in Rett syndrome [8], and the aberrant DNA methylation signatures observed in neuropsychiatric disorders, including schizophrenia and bipolar disorder [9]. The gene discussed is MECP2; the disease is atypical Rett syndrome.