Genome-wide mapping of common and rare variant effects on adiposity across childhood

Our understanding of the genetic architecture of obesity is primarily based on studies of adults, with sparser data from childhood. Here, we conducted age-stratified genetic association studies against objectively measured (n = 62,276) or recalled childhood adiposity-related traits (n_eff = 599,924), identifying 624 common variants associated with childhood adiposity, with one-third having no concordant association with adult body mass index. Signals linked to the leptin-melanocortin pathway (BSX, GNAS, LEPR and PCSK1) and incretin signaling (GIPR and GLP1R) showed childhood-specific effects on adiposity. Single-nucleus RNA sequencing data identified childhood-specific adiposity-regulating cell populations in the arcuate nucleus and mammillary bodies, indicating neurocircuits that regulate adiposity specifically during childhood. Finally, sequencing in 479,615 individuals uncovered rare protein-coding variation in ADCY3, CALCR, MC4R, MRAP2, POMC and MYH13, exhibiting stronger associations in childhood than in adults. Our findings suggest that childhood provides a more sensitive window for the study of key endocrine and neuropeptide pathways that regulate energy balance.