The potential role for OC as a predictive protein for GDM comes from previous studies relating knockout mice for GPRAC6A (OC receptor) and later smaller pancreatic islet size, lower insulin content, lower pancreatic weight, lower number of islets, lower insulin mRNA expression, and lower insulin secretion in response to osteocalcin with glucose intolerance [65]. The gene discussed is INS; the disease is gestational diabetes.