Acetylcholine receptor antibodies in myasthenia gravis are associated with greater risk of diabetes and thyroid disease.
OBJECTIVE
Myasthenia gravis (MG) may be associated with the presence of acetylcholine receptor antibodies (AChRAb) [seropositive MG (SPMG)] or their absence [seronegative MG (SNMG)]. Along with features of MG, the presence of the AChRAb may relate to the existence of other immune-mediated diseases. We sought to determine the association of SPMG with other potential autoimmune diseases.


METHODS
A retrospective evaluation of prospectively identified MG patients at a tertiary care center was performed, with patients separated into SPMG and SNMG. Prevalence of other immune-mediated disorders, as well as the epidemiology, sensitivity of diagnostic testing, and thymic pathology, was contrasted between both patient groups.


RESULTS
Of the 109 MG patients identified, 66% were SPMG. SPMG was associated with a greater likelihood of significant repetitive stimulation decrement, the presence of either thymoma or thymic hyperplasia, and the presence of thyroid disease. In addition, all patients with a diagnosis of diabetes, concurrent with MG, were found to be SPMG.


CONCLUSIONS
AChRAb and SPMG impart not only a distinctive clinical and electrophysiological phenotype of MG, but are also associated with the heightened presence of endocrinological disease.
Toth
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C
Department of Clinical Neurosciences, University of Calgary and the Calgary Health Region, Calgary, Alberta, Canada. corytoth@shaw.ca
McDonald
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D
Oger
J
J
Brownell
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K
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000416:Alberta / Q000453:epidemiology; D001323:Autoantibodies / Q000097:blood*; D015984:Causality; D002648:Child; D015897:Comorbidity; D003920:Diabetes Mellitus / Q000453:epidemiology / Q000276:immunology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000097:blood / Q000453:epidemiology / Q000276:immunology*; D015995:Prevalence; D011446:Prospective Studies; D011950:Receptors, Cholinergic / Q000276:immunology*; D012189:Retrospective Studies; D012306:Risk; D017678:Sex Distribution; D013945:Thymoma / Q000276:immunology / Q000503:physiopathology; D013953:Thymus Neoplasms / Q000276:immunology / Q000503:physiopathology; D013959:Thyroid Diseases / Q000453:epidemiology / Q000276:immunology* / Q000503:physiopathology
D001323:Autoantibodies; D011950:Receptors, Cholinergic