title: Screening with the FMR1 protein test among mentally retarded males.
abstract: The fragile X syndrome is characterized by X-linked mental retardation with additional features such as a long face with large protruding ears, macroorchidism, and eye-gaze avoidance. The disorder is caused by an abnormally expanded CGG repeat within the first exon of the fragile X mental retardation (FMR1) gene that is associated with shutdown of transcription and absence of the fragile X mental retardation protein (FMRP). Detection of patients and carriers of the fragile X syndrome is done by DNA analysis of the CGG repeat, whereas the FMRP antibody test allows rapid detection of male patients using bloodsmears. In a screening program for the fragile X syndrome in the southwest of the Netherlands, 412 males with mental retardation of unknown cause were subjected to the protein test. The patients were scored for fragile X features and their DNA tested for the FMR1 mutation, as reported previously. The FMRP test detected two fragile X patients with a repeat expansion in FMR1, whereas normal protein expression was observed in all the retarded male patients with a normal repeat. The FMRP test was found to be suitable for screening among a large population of retarded males. The results also suggest that mutations other than the CGG repeat leading to absence of detectable FMRP are apparently rare among mentally retarded males.
authors.affiliation: Department of Clinical Genetics, University Hospital Dijkzigt and Erasmus University, Rotterdam, The Netherlands. devries@kgen.fgg.eur.nl
authors.forename: B B
authors.initials: BB
authors.lastname: de Vries
authors.forename: S
authors.initials: S
authors.lastname: Mohkamsing
authors.forename: A M
authors.initials: AM
authors.lastname: van den Ouweland
authors.forename: D J
authors.initials: DJ
authors.lastname: Halley
authors.forename: M F
authors.initials: MF
authors.lastname: Niermeijer
authors.forename: B A
authors.initials: BA
authors.lastname: Oostra
authors.forename: R
authors.initials: R
authors.lastname: Willemsen
mesh_terms: D000906:Antibodies; D051860:Fragile X Messenger Ribonucleoprotein 1; D005600:Fragile X Syndrome / Q000175:diagnosis*; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D008607:Intellectual Disability / Q000209:etiology*; D008297:Male; D009419:Nerve Tissue Proteins / Q000032:analysis*; D016601:RNA-Binding Proteins
chemical_list: D000906:Antibodies; D051860:Fragile X Messenger Ribonucleoprotein 1; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; C497683:FMR1 protein, human