Validating gene-brain-behavior associations in autism: A replication study

Autism is characterized by heterogeneity in clinical characteristics, neuroimaging and genetic profiles. To elucidate the multi-level heterogeneity, Buch et al. (2023) identified biologically meaningful subgroups in Autism Brain Imaging Data Exchange (ABIDE). However, ABIDE contains non-biological sources of variability due to retrospectively aligned site protocols. To separate biological from site-related variability and test the robustness of these subgroups, we assessed how well their findings replicate in a deeply phenotyped, prospectively collected autism dataset (EU-AIMS LEAP).

We included 270 autistic (7.5-30.3 years; 73% male) and 216 non-autistic participants (6.9-31 years; 63.4% male) from LEAP. Regularized canonical correlation analysis (RCCA) was conducted between functional connectivity and three clinical measures (verbal IQ [VIQ], and Autism Diagnostic Observation Schedule-2 [ADOS-2] social affect [SA] and restricted/repetitive behavior [RRB]). Next, subgroups identified by hierarchical clustering based on canonical variates were characterized by behavior, functional connectivity patterns and gene enrichment analyses.

Three of four autistic subgroups showed behavioral profiles consistent with the original study. Three subgroups shared stronger thalamocortical connectivity, while all four displayed distinct connectivity involving default mode network (DMN), salience (SN), visual and somatomotor networks. These subgroup-specific connectivity patterns were further linked to autism-associated and attention deficit hyperactivity disorder (ADHD)-related gene sets. Across preprocessing pipelines, subgroup assignments were partially preserved. Subgroup2 (globally affected behaviors) and Subgroup4 (less social difficulty, but more restricted behavior) retained more consistent behavioral profiles and connectivity alterations, whereas Subgroup1 and Subgroup3 were more sensitive to the precise preprocessing steps.

These four subgroups showed partly consistent behavioral profiles, connectivity alterations and genetic patterns, extending our understanding of the multi-level heterogeneity of autism.