In the age group of 20–39, we found no difference in the age at onset (P = 0.17), however, those with variant type are more associated with anti-GAD negative people (OR, 5.1; 95% CI, 1.9 to 13.6; P = 0.0003), and also with flu-like syndrome at the onset (OR, 4.8; 95% CI, 1.4 to 15.49; P = 0.022) (Supplementary Table 3), consistent with the observation in all T1D. Here, GAD1 is linked to type 1 diabetes mellitus.