While the relationship between perforin deficiency and HLH has been established, there are paradoxical reports of the association of TNFα and HLH, with cases of successful treatment of refractory HLH with TNFα inhibitors44,48 as well as cases of development of HLH after treatment with TNFα inhibitors49,50 being reported. The gene discussed is TNF; the disease is hyperinsulinemic hypoglycemia, familial, 4.