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  • Updated 10.16.2023
  • Released 12.03.2010
  • Expires For CME 10.16.2026

Anti-GQ1b antibody syndrome



Prior to the discovery of IgG antibodies against GQ1b, there were clinical variants that were considered linked to Guillain-Barré syndrome due to common clinical features shared with Guillain-Barré syndrome. The most notable are Miller Fisher syndrome, which is characterized by acute ophthalmoplegia, ataxia, areflexia, and Bickerstaff brainstem encephalitis, in which consciousness is also affected. Following the discovery of an association of GQ1b antibodies with Miller Fisher syndrome in 1992, other neurologic presentations with similar serological profiles emerged in the literature, including Bickerstaff brainstem encephalitis, acute ophthalmoplegia, acute ataxic neuropathy, pharyngeal-cervical-brachial weakness, and acute vestibular syndrome. In this article, the author discusses the current understanding behind the anti-GQ1b antibody syndrome.

Key points

• Anti-GQ1b antibody syndrome represents a group of disorders that share a common serological profile.

• GQ1b antibodies are a serological marker of Miller Fisher syndrome and Bickerstaff brainstem encephalitis but have been detected in other neurologic syndromes.

• The overall prognosis is good even without immunotherapy in those patients who have typical Miller Fisher syndrome or acute ophthalmoplegia, but intravenous immunoglobulin (IVIg) or plasma exchange is recommended when there is altered consciousness, limb weakness, or bulbar palsy.

• Important mimics to be excluded include brainstem syndromes of other etiologies and neuromuscular junction disorders. GQ1b antibody positivity in this context helps the differential diagnosis.

• Miller Fisher syndrome and Bickerstaff brainstem encephalitis can occur in association with a COVID-19 infection, but no patients have tested positive for GQ1b antibodies, indicating that a novel antigen might be implicated in the mechanism. However, GQ1b antibody-positive Miller Fisher syndrome following COVID-19 vaccination has been reported.

Historical note and terminology

The most recognizable variant of Guillain-Barré syndrome is Miller Fisher syndrome, which was first described in 1956 by Charles Miller Fisher. He reported three patients who presented with a triad of total external ophthalmoplegia, ataxia, and areflexia after an upper respiratory tract infection (15). The presence of cerebrospinal fluid (CSF) albuminocytological dissociation and antecedent infection likened Miller Fisher syndrome to Guillain-Barré syndrome.

Prior to this, in 1951, Bickerstaff and Cloake described three patients who presented with prominent drowsiness followed by brainstem signs causing ophthalmoplegia, facial palsy, bulbar palsy, and ataxia following a prodrome of infective illness. The etiology of this condition was speculated to be similar to that of Guillain-Barré syndrome based on the presence of prodromal symptoms in all three patients, areflexia with CSF albuminocytological dissociation in one patient, and subsequent recovery of neurologic symptoms in all three patients (06). Six years later, Bickerstaff extended his observations including an additional five patients with similar patterns of brainstem signs, emphasizing the benign outcomes in all but one patient, who died following a seizure (05). This condition has since been referred to as Bickerstaff brainstem encephalitis.

In 1992, Chiba and colleagues identified IgG antibodies against ganglioside GQ1b in six patients with typical Miller Fisher syndrome (09). The GQ1b IgG antibodies were initially considered as a serological marker of Miller Fisher syndrome. However, the antibodies were also detected in patients with acute postinfectious ophthalmoplegia without ataxia (07), Guillain-Barré syndrome with ophthalmoplegia (07), and Bickerstaff brainstem encephalitis (84; 26). The latter findings supported the continuity between the two syndromes, with Miller Fisher syndrome representing one end of the spectrum and Bickerstaff brainstem encephalitis the other. Patients with milder clinical features, such as ophthalmoparesis without ataxia (82), or more extensive involvement with limb weakness (49), were also found to have GQ1b IgG antibodies on serological testing. In view of the common serological profile shared by this group of patients, it has been referred to as "anti-GQ1b antibody syndrome" (68).

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