CID constitute a large group of diseases, including some associated with a higher risk of extensive or disseminated varicella infection, such as autosomal recessive (AR) DOCK8 deficiency (15) and other PIDs related to actin-cytoskeleton abnormalities (16) (due to T-cell homing defect), in diseases with NK cell deficiencies among broader cellular deficiencies (AD GATA2 deficiency or AR MCM4 or GINS1 deficiencies) (17–19), AR DOCK2 deficiency, a PID that affect both innate and adaptive immunities, in which disseminated and fulminant varicella has been reported (20–22). The gene discussed is MCM4; the disease is combined immunodeficiency.