Social Communication and Interactions Symptoms in Fragile X Syndrome: The Underlying Comorbidities of Autism Spectrum Disorder and Anxiety

Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability. The genetic syndrome is often accompanied by high rates of comorbid autism spectrum disorder (ASD) and anxiety. Many symptoms of FXS and ASD overlap, and symptoms of anxiety may appear to be symptoms of ASD. Further, changes in DSM-5 ASD criteria may affect the prevalence of ASD in FXS. The present study examined the prevalence of individuals with FXS who met diagnostic criteria for ASD, especially social communication impairments within the context of DSM-5 changes, and examined parent-reported anxiety as a predictor of ASD diagnosis. A total of 74 participants between the ages of 12 and 40 were administered the Stanford-Binet, 5th Edition, Autism Diagnostic Observation Schedule, 2nd Edition (ADOS-2), Social Communication Questionnaire (SCQ), and Anxiety Depression and Mood Scale. ASD symptoms were examined across 4 methods: 1) Met based on ADOS-2; 2) met cut-off on the SCQ; 3) met ASD criteria for both ADOS-2 and SCQ; and 4) met based on DSM-5 criteria. The percentage of individuals meeting study diagnostic determination (ADOS-2 + SCQ) for ASD (28%) was similar to previous reports, and was slightly lower than the percentage meeting for the DSM-5 (37%). More individuals met SCI criteria than RRBI criteria. More males met criteria for all ASD variables than females. Multiple regression analyses indicated that parent-reported anxiety did not predict any ASD variables; rather age and nonverbal intelligence were predictive of most ASD variables. Cognitive functioning and variable RRBI symptoms may predict ASD in FXS more strongly than anxiety.Bachelor of Art