The prevalence of Rett syndrome in Fukui prefecture

The present study was performed to estimate the prevalence of Rett syndrome in Fukui prefecture by sending questionnaires to special classes (classes for handicapped children in schools for normal children) and schools for mentally/physically handicapped children, and observing children suspected of having this syndrome on the basis of answers to the questionnaire. The subjects were girls aged 6–14 years who were attending 11 special classes and 7 schools for handicapped children. The prevalence of Rett syndrome was estimated to be 0.22 per 10,000 girls aged 6–14 years in Fukui prefecture, as of April 1, 1993. The prevalence noted in this study was lower than those found in previous studies in Japan and Western countries.