Fever and headachesNo pharyngitis or palpable LNWBC 7.9K with L 34%, +1 reactive lymphocytes; thrombocytopenia, increased liver enzymes, and acute renal failureSyphilis and Coxiella Ab−; parvovirus IgG+ IgM−; EBV and hepatitis A/B/C virus serology panels negative; Toxo Ab NDCSF normalCT of chest, abdomen, and pelvis with HSM. The gene discussed is CD40LG; the disease is Fever.