Cognition, academic achievement, and adaptive behavior in school-aged girls with fragile X syndrome

Fragile X syndrome (FXS) is the leading monogenic cause of intellectual disability and autism in males and females. Females with FXS typically display a milder cognitive phenotype than males, despite experiencing significant developmental, behavioral, and social-emotional issues. To measure and distinguish the cognitive-behavioral profile of girls with FXS relative to verbal IQ-matched peers. Ninety-seven participants (N =55, N =42) six to 16 years of age completed assessments evaluating cognition, academic achievement, and adaptive behavior. The comparison group consisted of age-, sex-, and verbal IQ-matched peers. Consistent with previous studies, the FXS group demonstrated mean cognitive skills, academic achievement, and adaptive behavior in the borderline to low average range. On average, the FXS group showed poorer nonverbal reasoning, visual pattern recognition, verbal abstraction, math abilities, attention, inhibitory control, and working memory than the comparison group. There were no significant group differences in adaptive behavior. Different patterns of associations between cognition and selected outcomes emerged in each group. Results highlight the importance of identifying specific cognitive-behavioral profiles in girls with FXS to inform more targeted interventions for optimizing outcomes and quality of life in this population.