title: Systematic screening for fragile X syndrome in a cohort of 574 mentally retarded children.
abstract: In this study, we evaluated the prevalence of the fragile X syndrome in a cohort of 574 mentally retarded children. The only inclusion criterion was the diagnosis of mental retardation according to the DSM-IIIR classification. We used a PCR-based strategy for the diagnosis of fragile X syndrome to facilitate systematic screening. This diagnostic scheme is based on an initial PCR to eliminate most fragile X-negative patients followed by Southern blotting for fragile X syndrome diagnosis. Altogether, 403 boys and 171 girls were tested. The prevalence of this genetic disorder was 1.9% (11/574) in the whole cohort and 2.5% (10/403) in boys. Only one case of fragile X syndrome was detected among the 171 girls tested (0.6%). Clinical examination, especially in the youngest children, was often unremarkable, and the only reason for suspecting fragile X syndrome was the presence of mental retardation. Thus, a systematic screening for the fragile X syndrome in mentally retarded children seems justified because of the importance of a precise diagnosis in genetic counseling.
authors.affiliation: Laboratoire de Biochimie Génétique, Hôpital Robert Debré, Paris, France.
authors.forename: B
authors.initials: B
authors.lastname: Gérard
authors.forename: M F
authors.initials: MF
authors.lastname: Le Heuzey
authors.forename: G
authors.initials: G
authors.lastname: Brunie
authors.forename: P
authors.initials: P
authors.lastname: Lewine
authors.forename: M C
authors.initials: MC
authors.lastname: Saiag
authors.forename: V
authors.initials: V
authors.lastname: Cacheux
authors.forename: F
authors.initials: F
authors.lastname: Da Silva
authors.forename: M
authors.initials: M
authors.lastname: Dugas
authors.forename: M C
authors.initials: MC
authors.lastname: Mouren-Simeoni
authors.forename: J
authors.initials: J
authors.lastname: Elion
authors.forename: B
authors.initials: B
authors.lastname: Grandchamp
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005600:Fragile X Syndrome / Q000453:epidemiology / Q000235:genetics*; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D015995:Prevalence