Immunodeficiency 27A (IMD27A) [MIM:209950]: A form of Mendelian susceptibility to mycobacterial disease, a rare condition caused by impairment of interferon-gamma mediated immunity. It is characterized by predisposition to illness caused by moderately virulent mycobacterial species, such as Bacillus Calmette-Guerin (BCG) vaccine, environmental non-tuberculous mycobacteria, and by the more virulent Mycobacterium tuberculosis. Other microorganisms rarely cause severe clinical disease in individuals with susceptibility to mycobacterial infections, with the exception of Salmonella which infects less than 50% of these individuals. Clinical outcome severity depends on the degree of impairment of interferon-gamma mediated immunity. Some patients die of overwhelming mycobacterial disease with lepromatous-like lesions in early childhood, whereas others develop, later in life, disseminated but curable infections with tuberculoid granulomas. {ECO:0000269|PubMed:10811850, ECO:0000269|PubMed:11139207, ECO:0000269|PubMed:15589309, ECO:0000269|PubMed:16195661, ECO:0000269|PubMed:16715106, ECO:0000269|PubMed:17514500, ECO:0000269|PubMed:20015550, ECO:0000269|PubMed:20186794, ECO:0000269|PubMed:22708048, ECO:0000269|PubMed:25592983, ECO:0000269|PubMed:27868075, ECO:0000269|PubMed:28744922, ECO:0000269|PubMed:9389728}. Note=The disease is caused by mutations affecting the gene represented in this entry.; Immunodeficiency 27B (IMD27B) [MIM:615978]: A form of Mendelian susceptibility to mycobacterial disease, a rare condition caused by impairment of interferon-gamma mediated immunity. It is characterized by predisposition to illness caused by moderately virulent mycobacterial species, such as Bacillus Calmette-Guerin (BCG) vaccine, environmental non-tuberculous mycobacteria, and by the more virulent Mycobacterium tuberculosis. Other microorganisms rarely cause severe clinical disease in individuals with susceptibility to mycobacterial infections, with the exception of Salmonella which infects less than 50% of these individuals. Clinical outcome severity depends on the degree of impairment of interferon-gamma mediated immunity. Some patients die of overwhelming mycobacterial disease with lepromatous-like lesions in early childhood, whereas others develop, later in life, disseminated but curable infections with tuberculoid granulomas. IMD27B commonly presents with recurrent, moderately severe infections with environmental mycobacteria or BCG. Salmonellosis is present in about 5% of patients. {ECO:0000269|PubMed:10192386, ECO:0000269|PubMed:11335768}. Note=The disease is caused by mutations affecting the gene represented in this entry.