Accordingly, recent work [143] has demonstrated that two different animal models of autism—a model of Rett syndrome and the prenatal exposure to valproic acid—showed increased levels of ATM and decreased egr4 activity on the Kcc2b promoter, leading to decreased expression of Mecp2 and a delayed GABAergic developmental shift. The gene discussed is MECP2; the disease is atypical Rett syndrome.