Which feature best distinguishes type 2 autoimmune hepatitis from type 1?
- A Association with anti-mitochondrial antibody
- B Hypergammaglobulinemia restricted to IgG4
- C Presence of anti-liver-kidney microsomal antibody targeting CYP2D6 ✓
- D Exclusive occurrence in adults over 50 years
Correct answer: C. Presence of anti-liver-kidney microsomal antibody targeting CYP2D6
Explanation
Type 2 AIH is defined by anti-LKM1 antibodies directed against CYP2D6, occurs predominantly in children and young women, and carries a higher relapse rate. Type 1 features ANA and anti-smooth muscle antibody with polyclonal IgG elevation. Anti-mitochondrial antibody defines primary biliary cholangitis, and IgG4 relates to IgG4-related sclerosing cholangitis.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.