Rett Syndrome

Research from G. Lesca and co-authors yields new data on mental retardation

Rett Syndrome Library Library Home This article was published in Mental Health Weekly Digest, which you can subscribe to online.

"Mutations of the MECP2 (methyl-CpG-binding protein) gene mainly cause Rett syndrome but were also shown to be involved in mental retardation. This study aimed to estimate the frequency of MECP2 gene mutations in a,large group of mentally retarded patients without FRAXA expansion. Screening by heteroduplex analysis and SSCP followed by DNA sequencing of shifted bands were performed on 613 patients, including 442 males and 171 females. Eleven sequence variants were found, including nine polymorphisms. The two others may be pathogenetic. The first one, the double nucleotide substitution c. 1162_1163delinsTA leading to a premature stop codon (p.Pro388X) was found in a female patient with random X-inactivation, presenting with.borderline mental impairment without any features of Rett syndrome. The second one, the c.679C >G substitution, changing a glutamine to a glutamate in the transcriptional repression functional domain (p.Gln227Glu), was. found in a female patient with a moderately biased X-chromosome inactivation profile and presenting with mild intellectual delay and minor psychotic features. The low mutation rate suggests that a large-scale routine screening for MECP2 in mentally retarded subjects is not cost-effective in clinical practice," wrote G. Lesca and colleagues.

The researchers concluded: "Screening may be improved,by a pre-selection based on clinical features that remain to be established."

Lesca and colleagues published their study in European Journal of Medical Genetics (Mutation screening of the MECP2 gene in a large cohort of 613 fragile-X negative patients with mental retardation. European Journal of Medical Genetics, 2007;50(3):200-208).

For additional information, contact G. Lesca, Hopital Edouard Herriot, Service Genetics Molecular & Clinic, Genetics Laboratory, Batiment 7, F-69003 Lyon, France.

Publisher contact information for the European Journal of Medical Genetics is: Elsevier Science BV, PO Box 211, 1000 AE Amsterdam, Netherlands.

Keywords: France, Lyon, Developmental Disabilities, Genetics, Mental Retardation, Rett Syndrome.

This article was prepared by Mental Health Weekly Digest editors from staff and other reports. Copyright 2007, Mental Health Weekly Digest via NewsRx.com.