Unusual and coinfection in a child with a mutation: A case report and literature review.

and are the common opportunistic pathogens in immunodeficient patients. There have been no reports of and coinfection in immunodeficient children. Signal transducer and activator of transcription 1 () is a key transcription factor in immune responses. mutations are predominately associated with chronic mucocutaneous candidiasis and invasive mycosis. We report a 1-year-2-month-old boy diagnosed with severe laryngitis and pneumonia caused by and coinfection, which was confirmed by smear, culture, polymerase chain reaction and metagenome next-generation sequencing of bronchoalveolar lavage fluid. He has a known mutation at amino acid 274 in the coiled-coil domain of according to whole exome sequencing. Based on the pathogen results, itraconazole and trimethoprim-sulfamethoxazole were administered. This patient's condition improved, and he was discharged after two weeks of targeted therapy. In the one-year follow-up, the boy remained symptom-free without recurrence.