VTCN1 and type 1 diabetes mellitus: In addition, there were other studies suggested that small ubiquitin like modifier 4 gene (SUMO4) (Guo et al., 2004); members of B7 family, B7-H1 (CD274), B7-H3 (CD276) and B7-H4 (VTCN1) (Dai et al., 2014); genes in vitamin D metabolism and signaling (DHCR7 and VDR) genes (Cooper et al., 2011) were also candidate genes involved in the pathogenesis of T1D.