CMC susceptibility has been related to defects in T cell responses, mainly in IL-17-producing cells, such as Th17 and γ/δ T cells; individuals with mutations affecting the production of IL-17 and the proportion of Th17 cells (such as mutations in the genes IL17RA, IL17RC, IF17F, ACT 1, STAT3, AIRE, RORC, CARD9, IL12B, and IL12RB1, or GOF mutations in STAT1) suffer from CMC and other infections with variable severity [reviewed in (6, 7)]. The gene discussed is STAT1; the disease is infection.