Investigating facial phenotype in autism spectrum conditions: The importance of a hypothesis driven approach.

This commentary reviewed studies that found differences in the facial features of individuals with autism spectrum conditions (ASC) compared to typically developing individuals. While there is little agreement between studies, there is some support for asymmetrical facial features associated with ASC, and preliminary evidence that particular facial features relate to specific patterns of cognitive and behavioral symptoms. However, in light of inconsistencies between studies and based on accumulating understanding of etiological pathways, we propose an alternative approach to investigating facial differences in ASC.