Lymphopenia (700/μL; RV: 3200-12300*).Low IgG (332 mg/dL; RV: 345-213**), IgA (<8 mg/dL; RV: 14-106*) and IgM (<5 mg/dL; RV: 43-173**).Reduced proliferation assays.Multiple intestinal atresias, hepatopathy, coagulopathy, Klebsiella pneumoniae sepsis, portal hypertension with gastrointestinal bleeding. The gene discussed is CD40LG; the disease is lymphopenia.