Phenotypes and associated genotypes in these examples include (1) severe autoinflammation, a homozygous mutation in RNF31 (21); (2) Epidermodysplasia verruciformis, a homozygous mutation in STK4 (MST1) (22); (3) herpes simplex encephalitis, a homozygous mutation in UNC93B1 (23); (4) common variable immunodeficiency, a heterozygous mutation in IKZF1 (24); and (5) natural killer cell deficiency, compound heterozygous mutations in GINS1 (25). The gene discussed is IKZF1; the disease is immune system disorder.