paper, unless otherwise stated, study participants are of European ancestries. Transferability of PRS across populations is limited, with PRS generated from GWAS in one population usually providing attenuated predictive accuracy in other populations [21, 24]. Reasons for this include the use of tagging SNPs, differences in the patterns of linkage disequilibrium between populations, and SNP arrays biased to variants of European descent [25]. More importantly, differential genetic drift can cause unpredictable biases when scores inferred from one population are applied in another [26]. At an individual level, it is crucially important that an individual’s PRS is compared to a population-specific distribution so that the interpretation is valid. Progress in performing GWAS on non-European ancestries has been slow, with, for example, < 3% of study participants in the GWAS Catalog were of African ancestry [22]. Large-scale GWAS of diabetes and schizophrenia have been performed in African and East Asian populations [27–29], and novel initiatives of the collection in worldwide populations like the Human Heredity and Health in Africa (H3Africa) Initiative (https://h3africa.org/) and the African Mental Health Research Initiative (https://amari-africa.org) are underway. Key methodological considerations for GWAS in ancestrally diverse populations have been recently discussed, including the choice between performing a meta-analysis
