A search for X-chromosome uniparental disomy and DNA rearrangements in the Rett syndrome.

The cause of the Rett syndrome remains unknown but is thought to be related to X-chromosome abnormalities. Restriction fragment length polymorphism analysis was employed to search for X-chromosome DNA rearrangements and uniparental disomy in 16 probands and their families. Eighteen different probes, each specific for an area on either the long or the short arm of the X-chromosome, were used. DNA rearrangements were not detected at any of the tested loci. In addition, at each informative locus evidence of both maternal and paternal contributions was found in all probands. Thus, no evidence of either chromosomal abnormality or uniparental disomy was found in the population studied. If uniparental disomy is indeed a causative genetic mechanism for the Rett syndrome, its occurrence may only be infrequent.