STAT1 and cytomegalovirus infection: <h4>Background</h4>Chronic mucocutaneous candidiasis (CMC) is a heterogeneous primary immunodeficiency disease characterized by chronic or recurrent <i>Candida</i> infections of the skin, nails, and mucosa and is mostly associated with STAT1 gain-of-function (GOF) mutation (GOF-STAT1 mutation).<h4>Case presentation</h4>A two-year-old girl was presented with recurrent liver dysfunction, oral candidiasis, acute bronchial pneumonia, and cytomegalovirus infection.