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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(More)
The fragile X mental retardation syndrome is caused by unstable expansion of a CGG repeat in the FMR-1 gene. Clinical expression is associated with a large expansion of the CGG repeat. The mutation in the FMR-1 gene and the cytogenetic expression of the fragile site at Xq27.3 have been studied in 52 fragile X male patients. The percentage of the cytogenetic(More)
In this report we present the results of psychological investigations in a family in which 11 individuals, 7 females and 4 males, have a deletion of 1.6 Kb proximal to the CGG repeat of the FMR1. All 4 males with the deletion and 2 of the female carriers show characteristics of the fragile X clinical and behavioural phenotype. The findings in the present(More)
In this report we present the results of a study of the intellectual functioning and cognitive profile of 26 Prader-Willi syndrome (PWS) patients. The mean IQ score was 62.3 (range 39-96). In 13 patients a significant difference between verbal and performance IQ was found. In 10 of them the performance IQ was higher than the verbal. The results of subtest(More)
A cytogenetic study was performed in a population of 1170 mentally retarded and/or behaviourly disturbed patients of the Hondsberg Institute in the south of the Netherlands. The cytogenetic data are presented and discussed. In all patients chromosomal evaluation was performed with Giemsa-banding and Quinacrine fluorescence, and additional banding techniques(More)
In this study we present data on the adaptive behavior profile and on the development of adaptive functioning in 39 fragile X [fra(X)] males, age 4-26 years. Social adaptability is relatively well developed as compared to cognitive level and especially self-help skills continue to grow with age despite a stagnation in intellectual growth.
In this paper we review the data on intelligence in fra(X) males reported up to now in the literature, with special attention to its evolution with age. The available data suggest a decline in intellectual functioning in relation to age. These findings, however, should be interpreted with caution because of sampling and other methodological problems related(More)
In this paper we present data on the cognitive abilities analyzed by systematic, standardized psychometric testing in 18 fra(X) boys who participated in a multicenter, longitudinal study. In the majority of the patients no significant differences were found between verbal and performance intelligence. Higher performance IQ than verbal IQ was found primarily(More)