Several IEIs can present as HLH mimics, including diseases with impaired control of the inflammatory response (autoinflammatory disorders, DADA2, and complex diseases such as GATA2 deficiency), conditions within the ALPID spectrum (i.e., APDS, STAT3 GOF), and others [53,63]. The gene discussed is GATA2; the disease is hyperinsulinemic hypoglycemia, familial, 4.