When selecting for this high risk population, the cumulative risk of developing islet autoantibodies by age 10 years was not different between children carrying the TCF7L2 CT or TCF7L2 CC genotype (17%; 95% CI: 11–23%) and children carrying the type 2 diabetes protective TCF7L2 TT genotype (22%, 95% CI: 14–30%); (P = 0.321); HR 1.23, 95%CI: 0.75–2.2 (P = 0.360). Here, TCF7L2 is linked to type 2 diabetes mellitus.