[STAT1 gain-of-function mutation leading to disseminated Talaromyces marneffei infection combined with hemophagocytic syndrome: a case report].

heterozygous dominant mutation in the STAT1 gene (c.1151G>A, p.Gly384Asp), localized to the DNA-binding domain at amino acid position 384. This confirmed a STAT1 gain-of-function (STAT1-GOF) variant, which is consistent with the clinical phenotype of impaired antifungal immunity. Over the clinical course, the patient developed HLH. Following a two-week course of intravenous amphotericin B liposome (5 mg/kg per day), followed by oral voriconazole maintenance therapy (200 mg, twice daily), the patient exhibited significant improvements in clinical symptoms and laboratory parameters. Notably, the marked resolution of HLH was closely linked to the successful eradication of the fungal infection. This case highlights three critical clinical implications: (1) Patients with a predisposition to primary immunodeficiency disorders (e.g., STAT1-GOF mutations) should be evaluated for disseminated TM infections, even if they are HIV-negative; (2) mNGS is instrumental in etiological diagnosis and facilitates early intervention for fungal infections; (3) early identification of genetic defects establishes a theoretical basis for precision medicine and guides targeted therapeutic strategies.