Family environment and cognitive abilities in girls with fragile-X syndrome

There remains some variance in cognitive ability that is unexplained in children with fragile-X syndrome (FXS). Studies in typically developing children suggest that family environment might be one contributor to this unexplained variance. However, the effect of family environment in relation to cognition in atypical children with FXS has been relatively unexplored to date.

The present authors examined the putative genetic and environmental factors associated with cognition in a group of age-matched children consisting of 26 females with FXS and 31 typically developing children. All subjects were administered the Wechsler Intelligence Scale for Children-Revised; and the subjects' parents were administered the Wechsler Adult Intelligence Scale-Revised, and completed the Hollingshead Index of Social Status and the Moos & Moos Family Environment Scale.

Using a multiple regression analytic strategy, the present authors found that family environment contributed significantly to cognitive abilities in typically developing girls, but did not have a unique contribution to cognitive abilities in girls with FXS. There was a suggestion that, for girls with FXS, socio-economic status, a measure of sociocultural environment, was correlated with IQ.

The present study provides a basis for future research on the environmental contributions to cognitive abilities, particularly work related to verbal cognition.