PTPN22 and type 1 diabetes mellitus: In conclusion, current studies have elucidated that the CLEC16A gene is correlated with T1DM susceptibility in Caucasian, Japanese, and Chinese populations, indicating that, in addition to previously known genes, including HLA, insulin gene, PTPN22, and CTLA4, the CLEC16A gene is a newly discovered T1DM susceptibility gene.