Achieving accurate disease risk prediction using genetic information is a major goal in human genetics research and precision medicine. Accurate prediction models will have great impacts on disease prevention and early treatment strategies [1]. Advancements in high-throughput genotyping technologies and imputation techniques have greatly accelerated discoveries in genome-wide association studies (GWAS) [2]. Various approaches that utilize genome-wide data in genetic risk prediction have been proposed, including machine-learning models trained on individual-level genotype and phenotype data [3–8], and polygenic risk scores (PRS) estimated using GWAS summary statistics [9, 10]. Despite the potential information loss in summary data, PRS-based approaches have been widely adopted in practice since the summary statistics for large-scale association studies are often easily accessible [11, 12] while individual-level data are more difficult to acquire, deposit, and process. However, prediction accuracies for most complex diseases remain moderate, which is largely due to the challenges in both identifying all the functionally relevant variants and accurately estimating their effect sizes in the presence of linkage disequilibrium (LD) [13].