Heterozygous signal transducer and activator of transcription 1 (STAT1) gain-of-function (GOF) mutations have been discovered in 2011 [1, 2] as the cause of most inherited chronic mucocutaneous candidiasis (CMC), but follow-up studies have soon demonstrated that the STAT1-GOF disorder is extremely heterogeneous and determines an immune dysregulation syndrome characterized by a broad spectrum of bacterial, mycobacterial, viral, or other invasive fungal infections, autoimmunity or autoinflammatory manifestations, vascular aneurysms, and malignancies [3–5]. This evidence concerns the gene STAT1 and chronic mucocutaneous candidiasis.