A rare variant of primary immunodeficiency with a STAT1 GOF defect in the practice of a pulmonologist

Chronic mucocutaneous candidiasis is a complication occurring in patients with congenital immune disorders, characterized by recurrent infections of the skin, nails, and mucous membranes caused by C. albicans. The STAT1 gain of function (GOF) defect is a primary immunodeficiency condition resulting from heterozygous gain of function mutations in the STAT1 gene. STAT1 is a regulatory transcription factor and a key component of the JAK-STAT pathway mediating interferon-α/β/γ signaling. GOF mutations in the STAT1 gene lead to hyperphosphorylation of the protein of the same name and increased signaling along the JAK-STAT pathway, which also leads to impaired development of type 17 T helper cells (Th17). This disease most often debuts in childhood, and clinically, it is characterized by chronic mucocutaneous candidiasis, multiorgan autoimmune complications and an increased risk of infectious complications. The article describes the clinical observation of a girl with a rare variant of primary immunodeficiency STAT1 GOF.