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Fragile X syndrome in mildly mentally retarded children in a Northern Swedish county. A prevalence study
Author(s) -
Blomquist H. Kson,
Gustavson KH.,
Holmgren G.,
Nordenson I.,
PålssonStråe U.
Publication year - 1983
Publication title -
clinical genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 102
eISSN - 1399-0004
pISSN - 0009-9163
DOI - 10.1111/j.1399-0004.1983.tb00092.x
Subject(s) - fragile x syndrome , etiology , mentally retarded , trisomy , incidence (geometry) , pediatrics , chromosomal fragile site , medicine , intellectual disability , fragile x , down syndrome , psychology , psychiatry , chromosome , genetics , biology , developmental psychology , physics , gene , optics
In an extensive etiological study of an unselected series of mildly mentally retarded children (MMR) (IQ 50–70) born 1959–1970 in a northern Swedish county, 5 of 110 boys (4.5%) and none of 61 girls had a fragile site on the distal end of the X‐chromosome (Fra Xq 28). Consequently fragile X was seen in 2.9% of the total series of 171 children. In a combined series of severe and mild mental retardation, the incidence of the fragile X syndrome was calculated to be 1:3000 in the county of Vasterbotten. Next to trisomy 21 the fragile X syndrome was the most common single identified cause of MMR in boys. A cytogenetic investigation using special cultural conditions and banding techniques should be performed in cases of mental retardation of unclear etiology and in possible female carriers.