A large-scale cytogenetic study of the causes of intellectual disability (ID) in children from special schools and institutions was made in Taiwan between 1991 and 1996.
The screening methods and the identification of subjects with ID consisted of both clinical evaluation (i.e. photographs, questionnaires on family, pre-peri-and postnatal history, and hospital records, including IQ) and further laboratory studies for diagnosis (i.e. standard chromosome analysis, and if indicated, high-resolution banding, cytogenetic fragile-X study or molecular techniques).
A total of 11 892 patients were enrolled in this study.
After excluding the acquired causes of ID, such as infections and the sequelae of brain insults, or the well-known single-gene disorders and other multifactorial diseases, 4372 (36.8%) cumulative cases were recruited for karyotyping studies according to their phenotypes and medical records.
Abnormal karyotypes were noted in 1889 children (43.2% of all selected children).
Thus, the overall incidence of chromosomal aberrations in subjects with ID was estimated as 15.9%. Down's syndrome, the most common cause of ID, accounted for 82.4% of all patients with abnormal karyotypes.
The causes of ID were considered to be prenatal in 55.2% (n=6564) of cases, perinatal in 9.5% (n=1130), postnatal in 3.3% (n=392) and unknown in 32.0% (n=3805) of cases. (...)
Mots-clés Pascal : Arriération mentale, Etiologie, X fragile syndrome, Aberration chromosomique, Prévalence, Epidémiologie, Santé mentale, Taiwan, Asie, Homme, Déficience intellectuelle, Trouble développement, Fragilité chromosomique
Mots-clés Pascal anglais : Mental retardation, Etiology, Fragile X syndrome, Chromosomal aberration, Prevalence, Epidemiology, Mental health, Taiwan, Asia, Human, Intellectual deficiency, Developmental disorder, Chromosome fragility
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 98-0258924
Code Inist : 002B18D04A. Création : 11/09/1998.