TYK2 and type 1 diabetes mellitus: Recently, based on the discovery of natural mutations of TYK2 gene as murine encephalomyocarditis (EMC)-D virus-induced diabetes susceptibility gene causing deteriorated type 1 interferon (IFN) response (Izumi et al., 2015), we could show that “TYK2 promoter variant” in Japanese subjects is associated with an increased risk of T1D (Nagafuchi et al., 2015).