PTPN2 and type 1 diabetes mellitus: Moreover, among the 50 loci linked to T1D, several are expressed in beta-cells and involved in innate immunity [e.g. Protein Tyrosine Phosphatase, Non-Receptor Type 2 (PTPN2), Tyrosine Kinase 2 (TYK2), Interferon Induced Helicase C Domain 1 (IFIH1) and BTB Domain and CNC Homolog 2 (BACH2)].