IFNG and Mendelian susceptibility to mycobacterial diseases: Indeed, 18 of the 19 known monogenic etiologies of MSMD impair IFN-γ production (variants of IFNG, IL12B, IL12RB1, IL12RB2, IL23R, TYK2, ISG15, RORC, and TBX21), cellular responses to IFN-γ (IFNGR1, IFNGR2, STAT1, JAK1, USP18, and CYBB), or both (IKBKG, IRF8, and SPPL2A; Bustamante, 2020; Kerner et al., 2020; Yang et al., 2020; Martin-Fernandez et al., 2022).