So far, NKG2C+ NK cell expansion in SCID patients post HCMV infection was reported in a patient with IL-7 receptor deficiency exhibiting a T−B+NK+ phenotype [30], a patient with atypical Janus kinase 3 deficiency exhibiting a TlowB+NK+ phenotype [31] and patients with transporter associated with antigen presentation deficiency [32]. The gene discussed is JAK3; the disease is hyperinsulinemic hypoglycemia, familial, 4.