Characterising repetitive behaviours in young boys with fragile X syndrome

Repetitive behaviours are frequently observed in individuals with intellectual disability (ID). The present study examined the profile, inter-correlations and predictive correlates of repetitive behaviours in boys with fragile X syndrome (FXS), the leading inherited cause of ID. Specific child characteristics examined as predictors included anxiety, nonverbal cognition and autism social-affective symptomatology.

Participants were 39 boys with FXS (aged 6-10 years). Repetitive behaviours were measured using the Repetitive Behavior Scale - Revised (RBS-R) - a 43-item caregiver-report measure normed on individuals with ID.

Restricted Interests and Sensory Motor behaviours were reported as most problematic for this sample of boys, whereas Self-injurious behaviours were less problematic. All subscales of the RBS-R were significantly inter-correlated. Nonverbal IQ was negatively related, whereas anxiety and social affective symptoms of autism spectrum disorder were positively related, to scores for Restricted Interests. Anxiety was also positively related to scores for Compulsive behaviours and Ritualistic Sameness behaviours.

This study provides a preliminary description of repetitive behaviours in boys with FXS, which may form the groundwork for future research.