Genome-wide association studies (GWAS) of adiposity

Abstract

Adiposity is strongly heritable and one of the leading risk factors for type 2 diabetes, cardiovascular disease, cancer, and premature death. In the past 8 years, genome-wide association studies (GWAS) have greatly increased our understanding of the genes and biological pathways that regulate adiposity by identifying more than 100 novel susceptibility loci for overall adiposity and more than 70 loci for body fat distribution. The results for overall adiposity highlight a significant neuronal component, whereas loci regulating body fat distribution demonstrate a central role for adipocyte biology and insulin resistance in the pathophysiology. The effect sizes of all identified loci are small, and even in aggregate, they explain <3 % of the variance in each adiposity trait. This and other evidence suggest that numerous new loci will be identified in extended meta-analyses in the future. The translation of the new discoveries into clinical care remains a major challenge. As the first step, further studies are required to establish the causal genes and variants and to disentangle the exact physiological mechanisms underlying each genotype-phenotype association.