Heterogeneity in autism spectrum disorder explained by social-communicative and restricted repetitive behavior balance subgroups

Abstract

BackgroundAutism spectrum disorder (ASD) is characterized by phenotypic heterogeneity when it comes to the symptom profiles in the social communication (SC) and restricted repetitive behaviors (RRB) domain. To date, a two-factor (i.e., SC and RRB)/three-class model has been empirically shown to be the best fit in explaining the variability. The purpose of the study is to confirm the potential of previously introduced model, the SC-RRB balance subgroups, and investigate the phenotypic characteristics of these subgroups using a large well-characterized sample of autistic youth. MethodThe final sample extracted from the Simons Simplex Collection (SSC) consisted of 2744 autistic youth aged 4 – 18 years. We adopted the SC-RRB balance modeling used in Bertelsen et al. (2021) where subgroups were labeled based on the within-person difference between SC difficulties and level of RRB. A latent profile analysis (LPA) was conducted to validate the presence of the SC-RRB balance subgroups. ResultsData revealed similar SC and RRB scores to previous research. Significant differences in the demographic variables and core autism symptoms across SC-RRB balance subgroups were identified. The LPA indicated presence of three profiles with similar patterns. ConclusionsWe confirmed the potential of SC-RRB balance modeling in discriminating relatively homogeneous ASD subgroups. In addition to replicating previous findings in an independent sample, our data showed novel findings regarding sex, IQ, and specific ASD symptoms. Stratifying ASD into homogenous groups in a top-down approach could direct future research into unraveling differential pathogenesis and response to treatment.