Proteins including IgG, IgM, and albumin were low (IgG 228 mg/dL [reference range 650–1,600 mg/dL], IgM 41 mg/dL [reference range 50–300 mg/dL], albumin 1.7 g/dL [reference range 3.2–4.8 g/dL]), yet she displayed no signs of malnutrition, proteinuria, or synthetic liver dysfunction to explain the low protein levels. The gene discussed is CD40LG; the disease is malnutrition.