 This paper examines the development of a global polygenic risk score, PRS, for body mass index, BMI. The authors used a meta-analysis of genome-wide association studies, GWAS, from the giant consortium to generate a set of markers and affect estimates for use in a Bayesian approach to create a trans-ethnic PRS. This PRS was then applied to three different ethnicities, East Asian, Brazilian and European, and compared with population-specific PRS. The authors found that the trans-ethnic PRS outperformed the population-specific PRS in all three ethnicities, demonstrating its utility in predicting BMI across diverse populations. This article was authored by Huichi Chu, John J. Connolly, Peter Kraft and others.