Anti-MDA5 (anti-melanoma differentiation-associated gene 5) antibody is associated with which specific clinical phenotype in inflammatory myopathies?
- A Cancer-associated myositis with anti-TIF1γ positivity
- B Rapidly progressive interstitial lung disease with minimal myositis (amyopathic dermatomyositis) ✓
- C Anti-synthetase syndrome with mechanic's hands and polyarthritis
- D Overlap myositis with systemic sclerosis features
Correct answer: B. Rapidly progressive interstitial lung disease with minimal myositis (amyopathic dermatomyositis)
Explanation
Anti-MDA5 (CADM-140) antibody is specifically associated with clinically amyopathic dermatomyositis (CADM) and rapidly progressive ILD, which has high mortality (30–50% at 6 months without aggressive immunosuppression). Patients often have typical DM skin features (Gottron papules, heliotrope rash) but minimal or no muscle weakness. Anti-TIF1γ is associated with cancer risk in adults. Anti-Jo1 is the prototypic anti-synthetase antibody. Anti-PM-Scl is the overlap myositis marker.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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