Overview of Mendelian Susceptibility to Mycobacterial Diseases (MSMD).

Mendelian susceptibility to mycobacterial diseases (MSMD) refers to a group of genetic conditions predisposing an individual to environmental mycobacteria and other intracellular pathogens, leading to disseminated infection. Nine MSMD genes have been identified, which include seven autosomal (IFNGR1, IFNGR2, STAT1, IL12B, IL12RB1, ISG15, and IRF8) and two X-linked (NEMO and CYBB) genes. MSMD patients present with disseminated BCGosis or with symptoms of non-tuberculous Mycobacterium (NTM). Host defense mechanisms, such as the interferon (IFN) gamma and IL-12 pathways, which activate macrophages, play a crucial role in combating the Mycobacterium species. Treatment with interferon gamma and hematopoietic stem cell transplantation holds promise.