Anti-GQ1b antibody syndrome

Anti-GQ1b antibody syndrome refers to a spectrum of neurological conditions which share autoantibodies to the ganglioside complex GQ1b, and have overlapping clinical presentations. 

Clinical presentation

Typical anti-GQ1b antibody syndromes with ophthalmoplegia include ^1,3: 

• Miller Fisher syndrome

  • ophthalmoplegia, ataxia, and areflexia

• Bickerstaff brainstem encephalitis

  • altered conscious state, ophthalmoplegia, ataxia, and pyramidal signs (including hyperreflexia)

• acute ophthalmoparesis without ataxia

  • solely ophthalmoplegia, notably without ataxia or areflexia

• Guillain-Barré syndrome with ophthalmoplegia

Atypical or limited anti-GQ1b antibody syndromes that do not have ophthalmoplegia additionally include ³:

• acute vestibular syndrome

  • presents similarly to vestibular neuritis

• optic neuropathy with disc swelling

  • bilateral or unilateral optic neuropathy with disc swelling

• acute sensory ataxic neuropathy

  • similar to Miller Fisher syndrome but without ophthalmoplegia

Pathology

The exact relationship between these entities, and what determines the clinical phenotype remains unclear, possibly relating to the exact specificity of the anti-GQ1b IgG antibodies and how these are expressed throughout the nervous system ². The pathogenic role of anti-GQ1b IgM antibodies is unknown ³.

Treatment and prognosis

Management of anti-GQ1b antibody syndromes is generally with intravenous immunoglobulin, which may hasten the clinical recovery ³. Most patients make a full recovery within 12 weeks, although the prognosis is worse in patients with a Bickerstaff brainstem encephalitis or Guillain-Barré syndrome with ophthalmoplegia phenotype ³. Recurrence is rare, reported in 14% of cases ³.