Genetics link infant temperament to later behavior across diverse populations

This GWAS meta-analysis across European and multi-ancestry cohorts (up to ~78k infants) identifies ten loci associated with four temperament traits in the first three years: emotionality, activity, shyness, and sociability. SNP heritability ranges from ~3% to ~15%, two loci colocalize with adult cortex eQTLs (RHEBL1 and MR1), and genetic correlations link early temperament to adult neuroticism, ADHD, autism and extraversion. Findings replicate across ancestry groups, and polygenic scores explain modest variance, with within-family analyses supporting genetic influences on temperament.