Individuals with mutations in IL‐17A, IL‐17 receptor A (IL‐17RA), or IL‐17RC (Puel et al, 2011; Ling et al, 2015; Levy et al, 2016) are susceptible to chronic mucocutaneous candidiasis (CMC) as are patients with dominant‐negative mutations in the transcription factor signal transducer and activator of T cells (STAT) 3 (Milner et al, 2008) and gain‐of‐function (GOF) mutations in STAT1 (Toubiana et al, 2016), which result in defects of Th17 cell differentiation. The gene discussed is IL17RA; the disease is chronic mucocutaneous candidiasis.