Review of the literature identified a total of 10 patients with severe Toxoplasma infection involving five distinct gene defects along the IL-12/ IFN-γ loop: four cases of CD40L deficiency, one case of heterozygous mutation in NFKB2, two cases of IL-12Rβ1 deficiency, one case of STAT1 gain-of-function mutation, and two cases of autosomal recessive IFN-γR1 deficiency (23–30). The gene discussed is CD40LG; the disease is hyperinsulinemic hypoglycemia, familial, 4.