In our prior phenome-wide association study, we found a significant association between recessive nonsynonymous MAP3K15 variants and reduced HbA1c (β = −0.13 SD units, P = 2.16 × 10−15) and a suggestive protective association with T2DM (self-reported; OR = 0.73, 95% CI: [0.63–0.85], P = 2.71 × 10−5). This evidence concerns the gene MAP3K15 and type 2 diabetes mellitus.