A 28-year-old man presents with progressive bilateral ophthalmoplegia, trunk and limb ataxia, and areflexia over 5 days, following an upper respiratory infection 2 weeks ago. Nerve conduction studies show reduced sensory nerve action potentials without demyelination. Which antibody is most strongly associated with this condition?
- A Anti-GM1 IgG
- B Anti-MAG IgM
- C Anti-GQ1b IgG ✓
- D Anti-Hu
Correct answer: C. Anti-GQ1b IgG
Explanation
This presentation is classic Miller Fisher syndrome (MFS), a variant of Guillain-Barre syndrome characterized by the triad of ophthalmoplegia, ataxia, and areflexia. Anti-GQ1b IgG antibodies are detected in over 90% of MFS cases and are considered pathognomonic. Anti-GM1 IgG is associated with classic GBS (acute inflammatory demyelinating polyneuropathy) and acute motor axonal neuropathy (AMAN). Anti-MAG IgM is associated with chronic demyelinating neuropathy with monoclonal gammopathy. Anti-Hu is a paraneoplastic antibody.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.