STAT3 and hyperinsulinemic hypoglycemia, familial, 4: Simultaneously, STAT3-deficiency disease is categorized into two types: STAT3 LOF mutation disease comprises immunodeficiencies with syndromic features, while STAT3 GOF mutation disease involves immune dysregulation, especially regulatory T cell defects, according to the International Union of Immunological Societies in 2019 [30].