In this report, we used a tag single nucleotide polymorphism (SNP) approach to select genetic variants of candidate genes (APCS, CPE, IAPP, IDE, PCSK1 and PCSK2) implicated in IAPP metabolism (Figure S1) and tested their independent and joint associations with risk of T2D and beta cell dysfunction. The gene discussed is PCSK2; the disease is type 2 diabetes mellitus.