Autism (ASD) is often underdiagnosed in children with Down Syndrome (DS). Based on current literature, about 1 in 5 children with Down Syndrome also meet criteria for Autism, which is a higher prevalence than the general population. However, research on the dual diagnosis is limited, and the exact rate of comorbidity varies by study. Research continues to examine behaviors that differentiate children with DS from children with the dual diagnosis. One of the main characteristics of Autism is lacking social interest. Children with the dual diagnosis also may have more pronounced communication delays, sensory differences, and repetitive body movements (e.g., hand flapping, spinning, toe walking).