Rett syndrome and the 4th metatarsal

Rett syndrome,' an intellectually handicapping, probably genetic disorder affects around one in 10000 females2 and is remarkable for the absence of coexisting injury, disease or dysmorphism. As early as 1985, one of us (AMK) observed isolated shortening of the 4th metatarsal in some affected girls but not their families. The British Isles Survey for Rett Syndrome' and clinics organised by the UK Rett Syndrome Association have recently provided an opportunity for serial examinations of cases. Among the last 50 classic cases aged over 5 years, we have observed nine with this solitary anomaly (1 in 5-6 cases). It was not observed in family members. Both feet were usually affected. We are now examining residents and staff at the Royal Scottish National Hospital (Mental Handicap) as well as further consecutive cases of Rett syndrome and their families to compare prevalence in these groups.