Patient P-Jap (Minegishi et al., 2006) was the only TYK2-deficient patient reported to suffer from chronic mucocutaneous candidiasis, which was attributed to impaired IL-12 and IL-23 responses and defective Th17 immunity, as seen in patients with IL-12Rβ1 deficiency (de Beaucoudrey et al., 2008). Here, TYK2 is linked to Chronic mucocutaneous candidosis.