Biotinidase deficiency mimicking NMO: initiallyexhibiting symptoms in adulthood

Bottin L, Prud'honS, Giannesini C et al.  Multiple Sclerosis 21 (12) 1604-07 2015.  

Authors present first case of biotinidase deficiency presenting in young adulthood ; children and adolescents may present with vision loss and tetraparesis.  It was due in this case to a novel missense mutation and partly improved with oral biotin therapy.

Seropositive voltage gated calcium channels, utility

Jammoul A, Shayya L, Mente K et al.  Neurology Clinical Practice  2016; 6:409-418.

Authors differentiate "classic" group with limbic encephalitis or neuromyotonia (9.6% of total) and note the others had a panoply of diagnoses that were nonclassic.  The classic group was more likely to have high titers of ab, but there was overlap.  91 % of lcassic and 21 % of nonclassic had levels > 0.25 nM.  75 % of patietns in high level ab group had autoimmune disorders, and 75 % of patients with low level titers did not.  26 % of patients had a remote malignancy (active, remote, solid or hematologic) but not ab titer difference was noted among the groups .

Conclusions:  1.  High VGKC ab levels are found in patients with classic and other autoimmune disorderes,  Low level ab titers are seen in nonspecific and mostly nonautoimmune disorders

2.  The presence of VGKC antibodies rather than the level may serve as a marker of malignancy

Notes this is bad on a chart review of 6,032 patients who underwent evaluation .

The nonclassic group includes PNS and CNS diorders including neuropathy, dementia, ALS, CJD.  Some patietns had nonspecific symptoms such as stutering speech, nausea and vomting and orthostasis without diagnosis of neurologic disease.

Cancers were oftendiagnosed due towhole body CT/PET; 2 patietns had previously unknown cancer (Ovarian and lung).  Cancer occurred more commonly in those over age 45.  Many cases of ab finding were remote by over ten years from actual tumor.

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