Rare genetic defects in the IL-17 pathway indicated a non-redundant role of IL-17 in protective immunity against fungal infections, especially those caused by Candida albicans and rarely non-albicans species of Candida. Early on, it was observed that patients suffering from chronic mucocutaneous candidiasis (CMC) exhibit reduced production of IL-17 and IL-22 cytokines [13]. The gene discussed is IL17A; the disease is chronic mucocutaneous candidiasis.