In the present case, although the production of high-molecular-weight IGF-II from the tumor was not demonstrated, we considered her hypoglycemia to be attributable to NICTH because the patient had no other diseases that could have caused hypoglycemia (such as the aforementioned liver failure, adrenal failure, and insulinoma) and levels of IRI and C-peptide were low. The gene discussed is IGF2; the disease is neoplasm.