Single nucleotide polymorphisms (SNPs) in the gene encoding for the inhibitory receptor PD-1 (PDCD1) have also been identified and associated with increased T1D susceptibility [59,60], some of them being located at the binding site of RUNX1/AML1 transcription factors that are involved in cellular differentiation and regulation of hematopoiesis. The gene discussed is PDCD1; the disease is type 1 diabetes mellitus.