Prevalence of Rett syndrome in Switzerland

In an extensive survey, 35 cases of Rett syndrome born in Switzerland were found. Only 5 probands were older than 20 years; the oldest subject was 37. The prevalence for 1967-1982 was 0.41/10,000 (= 1:24,600) girls. This is considered a minimum prevalence since complete ascertainment was not possible by this investigation. Prevalence figures from southern Sweden and west of Scotland are higher (approximately 1:15,000). Rett syndrome is apparently responsible for a considerable proportion of girls with neurodegenerative disorders.