Mutations in 21 different genes (IFNGR1, IFNGR2, IFNG, IL12RB1, IL12RB2, IL23R, IL12B, ISG15, USP18, ZNFX1, TBX21, STAT1, TYK2, IRF8, CYBB, JAK1, RORC, NEMO, SPPL2A, MCTS1, and IRF1) with more than 35 different genetic etiologies of MSMD have been described [12,13,14,15,16,17,18]. This evidence concerns the gene TYK2 and Mendelian susceptibility to mycobacterial diseases.