GAD2 and type 1 diabetes mellitus: Among single glutamic‐acid decarboxylase 65 (GAD65) autoantibody‐positive participants (N = 158), those who carried ≥1 TCF7L2‐risk allele(s) had a lower progression rate to multiple autoantibody positivity (hazard ratio [HR] 0.65, p = 0.033) than those who did not, after adjusting for age and human leukocyte antigen (HLA) T1D‐risk haplotypes.