Given that our PRS is constructed predominantly with variants that are known to have strong effect sizes on T2D (S7 Table) and that these loci are well known [44] to represent defects in beta-cell function (including TCF7L2, KCNJ11, HNF4A, CDKAL1, MTNR1B, SLC30A8, and IGF2BP2), we call this cluster Probable Severe Insulin-Deficient Diabetes (pSIDD). This evidence concerns the gene TCF7L2 and type 2 diabetes mellitus.