By using around 10−4 as a criterion to select SNPs as IVs (Tables S22–S25 in Supporting 2), muti-GRAPPLE shows that DPP4 gene expression at the mRNA level affects HF independent to type-2 diabetes (effect: 0.25; CI, 0.01–0.45; p=0.04 for UKB. Here, DPP4 is linked to type 2 diabetes mellitus.