Mondo Description Any autosomal recessive mendelian susceptibility to mycobacterial diseases due to a complete deficiency in which the cause of the disease is a mutation in the IL12B gene.

Uniprot Description 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. IMD29 is characterized by undetectable IL12B secretion from leukocytes. Affected individuals generally present with BCG disease after vaccination in childhood, and at least half also have Salmonella infection. Disease phenotype is relatively mild, and patients have a good prognosis.