{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,11]],"date-time":"2026-05-11T17:50:45Z","timestamp":1778521845936,"version":"3.51.4"},"reference-count":33,"publisher":"Oxford University Press (OUP)","issue":"2","license":[{"start":{"date-parts":[[2020,11,12]],"date-time":"2020-11-12T00:00:00Z","timestamp":1605139200000},"content-version":"vor","delay-in-days":316,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the Mayo Clinic Foundation, the Center of Individualized Medicine and the Center for MS and Autoimmune Neurology"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2020,7,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:p>Delayed diagnosis of immune-mediated necrotizing myopathy leads to increased morbidity. Patients with the chronic course without 3-hydroxy-3-methylglutaryl-coenzyme-A reductase-IgG or signal recognition particle-IgG are often challenging to diagnose. Immunotherapy response can also be difficult to assess. We created a statistical model to assist immune-mediated necrotizing myopathy diagnosis. Electrical myotonia versus fibrillations were reviewed as biomarkers for immunotherapy treatment response. Identified were 119 immune-mediated necrotizing myopathy cases and 938 other myopathy patients. Inclusion criteria included all having electrophysiological evaluations, muscle biopsies showing inflammatory\/necrotizing myopathies, comprehensively recorded neurological examinations, and creatine kinase values. Electrical myotonia was recorded in 56% (67\/119) of retrospective and 67% (20\/30) of our validation immune-mediated necrotizing myopathy cohorts, and significantly (P\u2009&amp;lt;\u20090.001) favoured immune-mediated necrotizing myopathy over other myopathies: sporadic inclusion body myositis (odds ratio\u2009=\u20094.78); dermatomyositis (odds ratio\u2009=\u200910.61); non-specific inflammatory myopathies (odds ratio\u2009=\u20098.46); limb-girdle muscular dystrophies (odds ratio\u2009=\u20095.34) or mitochondrial myopathies (odds ratio\u2009=\u200914.17). Electrical myotonia occurred in immune-mediated necrotizing myopathy seropositive (3-hydroxy-3-methylglutaryl-coenzyme-A reductase-IgG 70%, 37\/53; signal recognition particle-IgG 29%, 5\/17) and seronegative (51%, 25\/49). Multivariate regression analysis of 20 variables identified 8 (including electrical myotonia) in combination accurately predicted immune-mediated necrotizing myopathy (97.1% area-under-curve). The model was validated in a separate cohort of 30 immune-mediated necrotizing myopathy cases. Delayed diagnosis of cases with electrical myotonia occurred in 24% (16\/67, mean 8\u2009months; range 0\u2013194). Half (8\/19) had a chronic course and were seronegative, with high model prediction (&amp;gt;86%) at the first visit. Inherited myopathies were commonly first suspected in them. Follow-up evaluation in patients with electrical myotonia on immunotherapy was available in 19 (median 21\u2009months, range 2\u2013124) which reduced from 36% (58\/162) of muscles to 7% (8\/121; P\u2009&amp;lt;\u20090.001). Reduced myotonia correlated with immunotherapy response in 64% (9\/14) as well as with median creatine kinase reduction of 1779\u2009U\/l (range 401\u20139238, P\u2009&amp;lt;\u20090.001). Modelling clinical features with electrical myotonia is especially helpful in immune-mediated necrotizing myopathy diagnostic suspicion among chronic indolent and seronegative cases. Electrical myotonia favours immune-mediated necrotizing myopathy diagnosis and can serve as an adjuvant immunotherapy biomarker.<\/jats:p>","DOI":"10.1093\/braincomms\/fcaa191","type":"journal-article","created":{"date-parts":[[2020,11,12]],"date-time":"2020-11-12T13:22:53Z","timestamp":1605187373000},"source":"Crossref","is-referenced-by-count":20,"title":["Diagnostic modelling and therapeutic monitoring of immune-mediated necrotizing myopathy: role of electrical myotonia"],"prefix":"10.1093","volume":"2","author":[{"given":"James D","family":"Triplett","sequence":"first","affiliation":[{"name":"Department of Neurology, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shahar","family":"Shelly","sequence":"additional","affiliation":[{"name":"Department of Neurology, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Guy","family":"Livne","sequence":"additional","affiliation":[{"name":"Guylivne.com, Boston, MA, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Margherita","family":"Milone","sequence":"additional","affiliation":[{"name":"Department of Neurology, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Charles D","family":"Kassardjian","sequence":"additional","affiliation":[{"name":"Division of Neurology, Department of Medicine, St. Michael\u2019s Hospital, University of Toronto, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0212-5697","authenticated-orcid":false,"given":"Teerin","family":"Liewluck","sequence":"additional","affiliation":[{"name":"Department of Neurology, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Cecilia","family":"Kelly","sequence":"additional","affiliation":[{"name":"Department of Neurology, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6212-1236","authenticated-orcid":false,"given":"Elie","family":"Naddaf","sequence":"additional","affiliation":[{"name":"Department of Neurology, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ruple S","family":"Laughlin","sequence":"additional","affiliation":[{"name":"Department of Neurology, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2443-0596","authenticated-orcid":false,"given":"Christopher J","family":"Lamb","sequence":"additional","affiliation":[{"name":"Department of Neurology, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Devon","family":"Rubin","sequence":"additional","affiliation":[{"name":"Department of Neurology, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Elliot L","family":"Dimberg","sequence":"additional","affiliation":[{"name":"Department of Neurology, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Divanshu","family":"Dubey","sequence":"additional","affiliation":[{"name":"Department of Neurology, Mayo Clinic, Rochester, MN, USA"},{"name":"Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"John R","family":"Mills","sequence":"additional","affiliation":[{"name":"Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jay","family":"Mandrekar","sequence":"additional","affiliation":[{"name":"Department of Neurology, Mayo Clinic, Rochester, MN, USA"},{"name":"Department of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Christopher J","family":"Klein","sequence":"additional","affiliation":[{"name":"Department of Neurology, Mayo Clinic, Rochester, MN, USA"},{"name":"Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"286","published-online":{"date-parts":[[2020,12,13]]},"reference":[{"key":"2021061905590629600_fcaa191-B1","doi-asserted-by":"crossref","first-page":"150","DOI":"10.1097\/MD.0000000000000028","article-title":"Anti-HMGCR autoantibodies in European patients with autoimmune necrotizing myopathies: inconstant exposure to 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