A patient presents with recurrent swelling of the lips as shown. He has no itching. Family history is positive. Which of the following is deficient in this patient?: (A) C1,C2,C4, (B) C1 inhibitor, (C) C3b inactivator, (D) C5-C8
Answer is B. This boy presents with features of hereditary angioneurotic edema, which is due to deficiency of C1 inhibitor. C1 inhibitor deficiency - Hereditary angioedema. C1, C2, C4 deficiency - Collagen vascular disorders C5-C8 deficiency - Recurrent bacteremia with Neisseria. Reference: Ananthanarayan and Paniker&;s Textbook of Microbiology Tenth edition