A severe neurodevelopmental disorder affecting the central nervous system. The disease is Monarch Disease Ontology term MONDO_0010726 (Rett syndrome). Also known as: RTS, RTT, Rett syndrome, X-linked dominant, Rett syndrome, atypical, X-linked dominant, Rett syndrome, preserved speech variant, X-linked dominant, Rett's disorder, Rett’s disease, cerebroatrophic hyperammonemia.