In our new model linking the progression of T1D and T2D to different subpopulations of insulin secretory granules in the same cells, we posit that the syt9 granules release their content primarily in the first phase of secretion during the initial spike in intracellular calcium supported by their close proximity to calcium channels (Hoppa et al., 2009). This evidence concerns the gene SYT9 and type 1 diabetes mellitus.