None of the type 2 diabetes susceptibility genotypes at the TCF7L2, CDKAL1, CDKN2A/2B, FTO, HHEX-IDE, HMGA2, IGF2BP2, KCNJ11, KCNQ1, MTNR1B, PPARG and SLC30A8 loci were associated with progression to type 1 diabetes (data not shown). Here, TCF7L2 is linked to type 1 diabetes mellitus.