Linguistic and cognitive profiles were examined in 18 children with autism and 18 children with fragile X syndrome (mean ages = 34 months). State-of-the-art diagnostic procedures for autism symptom identification were administered. Eight children with fragile X met criteria for autism. Comparison of linguistic and cognitive profiles (autism, fragile X without autism, fragile X with autism) revealed that children with fragile X (with autism) were more impaired in nonverbal cognition and expressive language. Receptive language was a relative strength for children with fragile X (without autism). There were no differences in receptive language in children with autism, regardless of fragile X status. Low receptive language may be a marker for autism symptoms in young children with fragile X.

The CCC-2 appears to provide an effective means to identify and characterize pragmatic language difficulties using a standardized approach in children with ASD and WS.

The association between nonverbal requesting (as measured by the Early Social Communication Scales) and problem-solving skills (as measured by an object retrieval task) was examined in 16 toddlers who had Down syndrome, 18 toddlers with developmental disabilities of mixed etiologies, and 19 typically developing infants and toddlers. Toddlers with Down syndrome showed fewer instrumental requests than did those in the typically developing group, but equal numbers of social routine requests. Toddlers with Down syndrome also showed poorer problem-solving strategies and received more help than children in both comparison groups on the object-retrieval task. Results showed a significant association between instrumental requests and problem-solving in the Down syndrome group. Implications for strengthening problem-solving skills in Down syndrome are discussed.

Background-Research suggests that children with Down syndrome may be at increased risk of having an autism spectrum disorder; however, previous studies have not utilized comprehensive, state-of-the-art diagnostic tools to address the question of comorbid autism and Down syndrome.