Thus, variants in genes affecting the production of IFNγ (e.g., IL12RB1, IL12RB2, IL23R, TYK2, IKBKG, SPPL2A, IRF8) or cellular responses to IFNγ (e.g., IFNGR1, IFNGR2, STAT1, JAK1) result in MSMD in otherwise healthy individuals [58]. Here, IFNG is linked to Mendelian susceptibility to mycobacterial diseases.