We here report the case of a 17-year-old female patient presenting with fever, abdominal pain, headache, nausea, transvaginal bleeding, and thrombocytopenia (platelet count 45,000 cells/mm<sup>3</sup>), who was diagnosed with DHF by positive dengue IgM and IgG antibodies on the fifth day of illness. The gene discussed is CD40LG; the disease is dengue disease.