Screening and diagnosis for the fragile X syndrome among the mentally retarded: an epidemiological and psychological survey. Collaborative Fragile X Study Group
The fragile X syndrome is an X-linked mental retardation disorder caused by an expanded CGG repeat in the first exon of the fragile X mental retardation (FMR1) gene. Its frequency, X-linked inheritance, and consequences for relatives all prompt for diagnosis of this disorder on a large scale in all affected individuals. A screening for the fragile X syndrome has been conducted in a representative sample of 3,352 individuals in schools and institutes for the mentally retarded in the southwestern Netherlands, by use of a brief physical examination and the DNA test. The attitudes and reactions of (non)consenting parents/guardians were studied by (pre- and posttest) questionnaires. A total of 2,189 individuals (65%) were eligible for testing, since they had no valid diagnosis, cerebral palsy, or a previous test for the FMR1 gene mutation. Seventy percent (1,531/2,189) of the parents/guardians consented to testing. Besides 32 previously diagnosed fragile X patients, 11 new patients (9 males and 2 females) were diagnosed. Scoring of physical features was effective in preselection, especially for males (sensitivity .91 and specificity .92). Major motives to participate in the screening were the wish to obtain a diagnosis (82%), the hereditary implications (80%), and the support of research into mental retardation (81%). Thirty-four percent of the parents/guardians will seek additional diagnostic workup after exclusion of the fragile X syndrome. The prevalence of the fragile X syndrome was estimated at 1/ 6,045 for males (95% confidence interval 1/9,981-1/ 3,851). On the basis of the actual number of diagnosed cases in the Netherlands, it is estimated that >50% of the fragile X cases are undiagnosed at present.
|Keywords||*RNA-Binding Proteins, Adolescent, Adult, Aged, Aged, 80 and over, Child, Child, Preschool, DNA/blood, Female, Fragile X Mental Retardation Protein, Fragile X Syndrome/*diagnosis/*epidemiology/genetics, Genetic Screening/methods/*psychology, Humans, Male, Middle Aged, Nerve Tissue Proteins/genetics, Netherlands/epidemiology, Patient Participation, Polymerase Chain Reaction/methods, Prevalence, Schools, Sensitivity and Specificity|
de Vries, B.B.A., Oostra, B.A., Niermeijer, M.F., Tibben, A., van den Ouweland, A.M.W., Mohkamsing, S., … Sandkuijl, L.A.. (1997). Screening and diagnosis for the fragile X syndrome among the mentally retarded: an epidemiological and psychological survey. Collaborative Fragile X Study Group. American Journal of Human Genetics. Retrieved from http://hdl.handle.net/1765/8723