Neurological disorders are often thought to be irreversible, but there have been several reports that some phenotypes can be reversed in mouse models, including Rett syndrome (20), Kabuki syndrome (21), Rubinstein–Taybi syndrome (22), SYNGAP1 deficiency (23), and autism spectrum disorders due to SHANK3 mutations (24). The gene discussed is SHANK3; the disease is atypical Rett syndrome.