Bi-allelic germline mutations in RORC, which encodes RORγ and RORγT transcription factors, have been associated with impaired systemic IFNγ response to mycobacteria but also with defective IL-17 mucocutaneous immunity to Candida. RORγ- and RORγT-deficient individuals can therefore display both mycobacteriosis and mucocutaneous candidiasis (recurrent or persistent oral candidiasis in 70% of the cases) (191). The gene discussed is IL17A; the disease is oral candidiasis.