IFNG and Mendelian susceptibility to mycobacterial diseases: Indeed, with the exception of ZNFX1 deficiency (ZNFX1 is a conserved and broadly expressed helicase that is recruited to, or induces stress granules), for which the mechanism of disease remains to be determined [171], all of the currently known monogenic etiologies of MSMD (which encompass mutations in as many as 18 genes and an even greater number of disorders due to the high degree of allelic heterogeneity) impair the production of, or cellular responses to IFN-γ [170,172].