Pearls about GQ1b

Serum and CSF GQ1 ab'sin isolated opthalmoplegic syndromes.  Spatola M, Du Pasquier R, Schluep M, et al.  Neurology 2016; 86:1780-1784

 

pearls about GQ1b from this article

 

1.  Antibodies are specific for Miller Fisher syndrome (MFS); unl;ike NMO-NMOSD, the use of the antibodies does not increase the spectrum of MFS substantially

 

2.  Measurement in CSF offers no additional value over serum

 

3.  Although ON (optic neuritis) can occur as part of the MFS, ISOLATED ON is NOT part of the MFS spectrum

 

4.  In acute opthalmoplegia, only 1/21 had positive antibodies but the antibodies occurred in 1/5 cases of AO of unknown etiology; therefore, the antibody may be useful as part of the evaluation of AO.  The cases with known etiology include diabetes, Tolosa Hunt and opsoclonus myoclonus

 

5. Low serum titers occur in several disorders and are markers of nonspecific damage to ocular motor nerve sheaths, while high concentrations are specific for MFS

 

6. IgG is the most relevant isotype antibody relevant for MFS, and GanglioCombi mixed IgM/IgG correlates well which makes it a viable alternative