SOCS1 and hyperinsulinemic hypoglycemia, familial, 4: In this regard, SOCS1 knockout (SOCS1−/−) mice uniformly suffer neonatal death by 3 weeks after birth, similar to the case for FoxP3 Treg deficiency, with unregulated IFNγ playing the central role in the malignant inflammation that is responsible for the fatal outcome (9).