The prevalence rate of TYK2 promoter variant is high in overall T1D (9.6%; OR, 2.4: p = 0.012), most highly in T1D associated with flu-like syndrome at diabetes onset (13.7%; OR, 3.6: p = 0.005), and anti-GAD Ab negative T1D (12.8%; OR, 3.3: p = 0.0021), compared with age- and sex-matched healthy controls (4.2%) (Nagafuchi et al., 2015). Here, TYK2 is linked to diabetes mellitus.