Autosomal dominant (AD) mendelian susceptibility to mycobacterial diseases (MSMD) due to partial interferon gamma receptor 2 (IFN-gammaR2) deficiency is a genetic variant of MSMD (see this term) characterized by a partial deficiency in IFN-gammaR2, leading to impaired response to IFN-gamma and, consequently, to recurrent, moderately severe infections with bacillus Calmette-Guérin (BCG) and other environmental mycobacteria (EM).