Hemophagocytic lymphohistiocytosis secondary to chronic mucocutaneous candidiasis caused by gain-of-function STAT1 mutations: a case report

Chronic mucocutaneous candidiasis disease is characterized by repeated or persistent candida albicans infection of the nail, skin, oral cavity and genital tract mucosa. This disease is rare in clinical practice. The patient in this case mainly presented with recurrent oral candidiasis, low body weight, and growth retardation. The examination on admission showed enlarged liver, spleen, and lymph nodes, and the laboratory tests showed low blood tertiary, hypofibrinogenemia, hypertriglyceridemia, high ferritin, low activity of NK cells, and the bone marrow smear showed hemophagocytic cells, and the peripheral blood metagenomic next generation sequencing, blood culture and bone marrow culture all suggested Candida albicans infection. Whole exon sequencing of the child revealed a heterozygous missense variation c.1154C>T (p.Thr385Met) in the STAT1 gene, which was a spontaneous variation. The diagnosis was acquired mutation in the STAT1 gene causing chronic mucocutaneous candidiasis disease secondary to hemophagocytic lymphohistiocytosis. The patient received anti-infection treatment with caspofungin and fluconazole successively, and was discharged from hospital after 5 weeks of hospitalization. No recurrence or sequelae were observed over 1 year after discharge.