Atypical forms of RTT, not reported in OMIM, have been described in patients not carrying mutations on FOXG1 nor MECP2 and manifesting additional phenotypes such as breathing abnormalities, spitting or drooling, unusual eye movements, cold hands and feet, irritability, sleep disturbances, seizures and scoliosis [32, 33]. This evidence concerns the gene FOXG1 and Rett syndrome.