Polygenic scores (PGS) were constructed in ALSPAC based on the largest publicly available samples for ASD (PGC ASD) and schizophrenia (PGC-SCZ2) as a training set, and then Z-standardised. The proportion of explained phenotypic variance in rank-transformed SCDC scores (Adjusted-R2) is displayed cross-sectionally at 8, 11, 14 and 17 years and given with respect to ASD-PGS (a) and schizophrenia-PGS (b). Nine different P-value thresholds PT for selecting risk alleles (PGS bins) in clinical samples are displayed. Starred P-values indicate the strength of the association (*P ≤ 0.05, **P ≤ 0.01 and ***P ≤ 0.001).
ALSPAC - Avon Longitudinal study of Parents and Children; ASD - Autism Spectrum Disorders; PGC-ASD - ASD collection of the PGC; PGC - Psychiatric Genomics Consortium ; PGC-SCZ2 - Samples of the second PGC mega-analysis of SCZ; PGS bin - Z-standardised polygenic scores according to threshold PT; SCDC - Social-Communication Disorder Checklist; SCZ - Schizophrenia