HIF3A and obesity due to melanocortin 4 receptor deficiency: However, the specific cell of origin for IPAs and signaling defects triggering IPA accumulation, and the relationship of different inducers of IPA accumulation to PDAC risk and presentation are not currently well defined, with suggestions that IPAs may arise from distinct causes as a result of acute or chronic pancreatitis, obesity, diabetes, or other pathogeneic stimuli.