Identifying cognitive and behavioral endophenotypes in families with autism spectrum disorders

Individuals with autism spectrum disorders (ASDs) demonstrate a wide variety of clinical resentations. Although the etiology is unknown, it is likely that ASDs result from a complex interaction of genetic and environmental factors. It may also be the case that there are multiple types of ASD, each with their own unique etiology and developmental trajectory. It has been difficult to identify homogeneous groups of individuals with ASD that in turn makes it difficult to discover any etiology. Neurocognitive characteristics of ASD may be a helpful way to find ASD subtypes. However, consistent neurocognitive patterns in ASD have not emerged. One potential method for studying genetic etiology is to examine nonautistic family members. Certain characteristics of ASD have been shown to occur in other family members at a subclinical level. These are known as endophenotypes or intermediate traits that may be genetically related to ASD. If subtypes of ASD can be identified based on neurocognitive profiles, those same profiles may also exist in some family members as endophenotypes. The present study aimed to examine the cognitive and behavioral profiles in families with ASDs. A cluster analysis utilizing constructs of IQ, language, social ability behavior, and adaptive behavior was performed on the affected family members. Similar methods and constructs were applied to unaffected family member data, and results were compared. Four clusters emerged in the affected