Mendelian susceptibility to mycobacterial disease (MSMD) is a rare inherited condition where mutations in autosomal genes in pathways involving interferon-γ (as well as interleukin-12, and tumor necrosis factor α, TNF-α) cause a primary immunodeficiency and predisposes individuals to a wide range of infections, including NTS35,36. The gene discussed is TNF; the disease is infection.