Fig. 2

Raw scatterplots and bivariate Pearson correlations among proband and sibling scores. Plots are shown for all VABS-II and MSEL scores found to be significantly associated among proband-sibling pairs in regression analyses. The left panel depicts proband-sibling associations between identical domains on the VABS-II (a, c, e), while the right panel depicts associations between proband scores on the VABS-II and sibling scores on related domains from the MSEL (b, d, f). Overall linear associations for the entire sample (all probands, all siblings) are depicted by black dashed regression lines with shaded gray confidence intervals; corresponding correlations (computed for ease of effect size interpretation) are denoted by gray boxes. Linear associations and Pearson correlations for concordant pairs (red) and discordant pairs (blue) are also shown. Significance levels are denoted as follows: ns, non-significant; *p < 0.05, **p < 0.01, ***p < 0.001. Generally stronger associations are found for concordant pairs in all domains, with individuals with ASD exhibiting a downward shift in score profiles for adaptive behavior and cognition. Highly similar patterns of proband-sibling associations are found for overall functioning (a, b), receptive language (c, d), and expressive language (e, f) using both parent-reported VABS-II measures and MSEL examiner-based assessments of sibling abilities at 24 months