GAD2 and type 1 diabetes mellitus: Specifically, TCF7L2‐T2D risk allele rs4506565, in linkage disequilibrium (LD) with T2D‐variant rs7903146, reduces the risk of progression to multiple autoantibody positivity among single GAD65 autoantibody‐positive subjects, particularly if T1D‐risk HLA‐haplotypes are absent.