In conclusion, human islet expression data suggest that variations in the level of expression of VPS13C and C2CD4A in the β-cell may contribute to altered T2D susceptibility in risk allele carriers, at least in females. The relatively mild effects of Vps13c ablation on glucose homeostasis are consistent with the hypothesis that changes in the expression of both genes may contribute to overall risk. Future functional studies will be required to determine the role of C2CD4A in the control of insulin secretion and the possible contribution of indirect mechanisms resulting from changes in the expression of either gene in extrapancreatic tissues.