Although serum calcium normalized following his neck surgery, he started to present with intermittent symptoms of hypoglycemia such as seizures associated with blood glucose levels of 1.6 to 1.8 mmol/L and serum insulin levels of 18.6 to 27.6 uIU/mL (I/G ratio: 0.63–0.85). The gene discussed is INS; the disease is Hypoglycemia.