IFNG and Mendelian susceptibility to mycobacterial diseases: Moreover, autosomal recessive (AR) complete IFN-γR1 (Jouanguy et al., 1996; Newport et al., 1996), IFN-γR2 (Dorman and Holland, 1998), and IFN-γ (Kerner et al., 2020) deficiencies are the only known etiologies of MSMD that clearly display complete penetrance in early childhood.