Contemplating syndromic autism

Abstract

Genetic factors contribute to the etiology of autism spectrum disorder (ASD), a group of neurodevelopmental conditions with an estimated population prevalence of 2.3%. Further elucidation of the genetic architecture underlying ASD continues. Against this backdrop, we review history and current use of the concept "syndromic autism", which refers to both genetic etiology and phenotypic co-comorbidity. We question whether this term is still helpful, both in clinical and in research contexts. We will outline the arguments in support of potentially abandoning usage of this construct and propose alternative strategies to facilitate the identification of clinically relevant subsets of individuals diagnosed with ASD. The emergence of the concept of syndromic autism, while understandable from a historical perspective, erroneously conflates two different attributions: genetic etiology and phenotypic co-morbidity. Current evidence indicates that these two components are independent, not only when the concept is used to describe individual patients, but also when used as a descriptor of (groups of) genes. Continued usage of distinction between syndromic versus non-syndromic autism may slow scientific progress and negatively affect clinical care. We propose that the use of scientifically valid and clinically useful distinctions will strengthen the evidence-base of clinical and research practice.