Mental status of females with an FMR1 gene full mutation.
The cloning of the FMR1 gene enables molecular diagnosis in patients and in carriers (male and female) of this X-linked mental retardation disorder. Unlike most X-linked disorders, a considerable proportion of the female carriers of a full mutation of the FMR1 gene is affected. In this study, the intelligence quotients (IQs) were ascertained by the Wechsler Adult Intelligence Scale in 33 adult females with a full mutation, with 28 first-degree adult female relatives (mainly sisters) without a full mutation as controls. Seventy-one percent of the females with a full mutation had IQ scores below 85. In paired analysis, no significant correlation could be detected between the IQs of the females with a full mutation and those of their first-degree female relatives, reflecting a dominant effect of the FMR1 gene full mutation in the mental development of females. Considering females with a full mutation only, we observed a significant relation between the proportion of normal FMR1 alleles on the active X chromosome and IQ. We present a model to explain this relationship.
de Vries
B B
BB
Department of Clinical Genetics, University Hospital Dijkzigt, Rotterdam, The Netherlands.
Wiegers
A M
AM
Smits
A P
AP
Mohkamsing
S
S
Duivenvoorden
H J
HJ
Fryns
J P
JP
Curfs
L M
LM
Halley
D J
DJ
Oostra
B A
BA
van den Ouweland
A M
AM
Niermeijer
M F
MF
D000328:Adult; D000368:Aged; D004247:DNA / Q000032:analysis; D005260:Female; D005600:Fragile X Syndrome / Q000235:genetics / Q000523:psychology*; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D008957:Models, Genetic; D009154:Mutation
D004247:DNA