Subsequently she had bruxism and developmental regression since she was 1 year and 6 months of age with loss of some motor and social skill. MECP2 study showed de novo nonsense mutation MECP2{NM_004992.3}:c.[808C>T];[=];MECP2{NP_004983.1}:p.[(Arg270∗)];[=] that confirmed the diagnosis of Rett Syndrome. This evidence concerns the gene MECP2 and Rett syndrome.