A 28-year-old woman has recurrent episodes of non-pitting, non-pruritic edema involving the face and extremities. C4 levels are low between attacks. The most likely deficiency is:

• A Factor H
• B CD59
• C C1 inhibitor ✓
• D Decay-accelerating factor

Explanation

B1 inhibitor deficiency causes hereditary angioedema, characterized by recurrent edema without urticaria and low B4 levels due to uncontrolled classical pathway activation. Factor H deficiency leads to atypical hemolytic uremic syndrome. CD59 and DAF deficiency cause paroxysmal nocturnal hemoglobinuria.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.