Snapshot A 2-month-old baby boy is brought in for an urgent visit to the pediatrician. He has had several ear infections in his short lifetime and now seems to be struggling with a cold. On physical exam, his tongue is noted to be coated with white film. His scalp and face are covered with a flaky dandruff-like substance. Immediately concerned, his pediatrician orders a chest radiograph, which shows absence of thymic shadow. Flow cytometry is ordered. Introduction Combined B- and T-cell disorder causing immunodeficiency Life-threatening disease of recurrent infections Pathogenesis login to view 13 more bullets Presentation Symptoms login to view 4 more bullets Physical exam login to view 6 more bullets Evaluation Diagnosis often delayed due to maternal IgG protecting baby in first few months of life ↓ Lymphocyte count (< 3000/μL) Chest radiography with no thymic shadow Flow cytometry login to view 2 more bullets Differential Diagnosis Hypogammaglobulinemia DiGeorge syndrome Hyper-IgM syndrome Ataxia-telangiectasia Treatment Bone marrow transplant login to view 2 more bullets Gene therapy Prognosis, Prevention, and Complications Prognosis login to view 2 more bullets Complications login to view 2 more bullets