{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,3]],"date-time":"2026-11-03T11:02:52Z","timestamp":1793703772330,"version":"4.5.1"},"reference-count":12,"publisher":"BMJ","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Reports"],"accepted":{"date-parts":[[2014,5,25]]},"abstract":"<jats:p>Mutations of the skeletal muscle voltage-gated sodium channel (NaV1.4) are an established cause of several clinically distinct forms of periodic paralysis and myotonia. Focal paresis has sometimes already been described. We report a case with atypical clinical manifestation comprising paramyotonia and cold-induced persistent and focal paralysis. A 27-year-old woman presented with paramyotonia congenita since her childhood. She experienced during her childhood one brief episode of generalised weakness. At the age of 27, she experienced a focal paresis lasting for several months. The known mutation p.Val1293Ile was found in the muscle sodium channel gene (SCN4A). Channel inactivation is involved in most Na<jats:sup>+<\/jats:sup> channelopathies. Fast inactivation is known to be responsible for the myotonia phenotype. We hypothesise that the V1293I mutation may also alter the slow inactivation in specific conditions, for example, prolonged cold exposure or prolonged and intensive exercise. This observation broadens the spectrum of clinical manifestations of this sodium channel mutation.<\/jats:p>","DOI":"10.1136\/bcr-2014-204430","type":"journal-article","created":{"date-parts":[[2014,6,17]],"date-time":"2014-06-17T08:26:15Z","timestamp":1402993575000},"page":"bcr2014204430","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":5,"title":["Focal and abnormally persistent paralysis associated with congenital paramyotonia"],"prefix":"10.1136","volume":"2014","author":[{"given":"Armelle","family":"Magot","sequence":"first","affiliation":[{"name":"Centre de R\u00e9f\u00e9rence Maladies Neuromusculaires Nantes-Angers, Nantes, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Albert","family":"David","sequence":"additional","affiliation":[{"name":"Service de g\u00e9n\u00e9tique m\u00e9dicale, Nantes, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Damien","family":"Sternberg","sequence":"additional","affiliation":[{"name":"Centre de R\u00e9f\u00e9rence des Canalopathies Musculaires, Service de Biochimie M\u00e9tabolique, ICM UMR_S975, Paris, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yann","family":"P\u00e9r\u00e9on","sequence":"additional","affiliation":[{"name":"Centre de R\u00e9f\u00e9rence Maladies Neuromusculaires Nantes-Angers, Nantes, France"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2014,6,17]]},"reference":[{"key":"2025082800333328000_2014.jun17_1.bcr2014204430.1","doi-asserted-by":"publisher","DOI":"10.1002\/ana.20241"},{"key":"2025082800333328000_2014.jun17_1.bcr2014204430.2","doi-asserted-by":"publisher","DOI":"10.1097\/00001756-199510010-00012"},{"key":"2025082800333328000_2014.jun17_1.bcr2014204430.3","doi-asserted-by":"publisher","DOI":"10.1016\/0022-510X(96)00173-6"},{"key":"2025082800333328000_2014.jun17_1.bcr2014204430.4","doi-asserted-by":"publisher","DOI":"10.1007\/s11910-011-0238-3"},{"key":"2025082800333328000_2014.jun17_1.bcr2014204430.5","doi-asserted-by":"publisher","DOI":"10.1016\/j.jns.2011.12.015"},{"key":"2025082800333328000_2014.jun17_1.bcr2014204430.6","first-page":"133","article-title":"A novel N440K sodium channel mutation causes myotonia with exercise-induced weakness\u2013exclusion of CLCN1 exon deletion\/duplication by MLPA","volume":"30","author":"Lehmann-Horn","year":"2011","journal-title":"Acta Myol"},{"key":"2025082800333328000_2014.jun17_1.bcr2014204430.7","doi-asserted-by":"publisher","DOI":"10.1212\/WNL.0b013e3182684683"},{"key":"2025082800333328000_2014.jun17_1.bcr2014204430.8","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-7793.1998.685bj.x"},{"key":"2025082800333328000_2014.jun17_1.bcr2014204430.9","doi-asserted-by":"crossref","first-page":"206","DOI":"10.1002\/0470846682.ch14","article-title":"Molecular mechanisms of gating and drug block of sodium channels","volume":"241","author":"Catterall","year":"2002","journal-title":"Novartis Found Symp"},{"key":"2025082800333328000_2014.jun17_1.bcr2014204430.10","doi-asserted-by":"publisher","DOI":"10.1016\/S0959-4388(03)00065-5"},{"key":"2025082800333328000_2014.jun17_1.bcr2014204430.11","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.2008.165787"},{"key":"2025082800333328000_2014.jun17_1.bcr2014204430.12","doi-asserted-by":"publisher","DOI":"10.1212\/01.wnl.0000265397.70057.d8"}],"container-title":["BMJ Case Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bcr-2014-204430","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,8,28]],"date-time":"2025-08-28T07:33:44Z","timestamp":1756366424000},"score":1,"resource":{"primary":{"URL":"https:\/\/casereports.bmj.com\/lookup\/doi\/10.1136\/bcr-2014-204430"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2014,6,17]]},"references-count":12,"alternative-id":["10.1136\/bcr-2014-204430"],"URL":"https:\/\/doi.org\/10.1136\/bcr-2014-204430","relation":{},"ISSN":["1757-790X"],"issn-type":[{"value":"1757-790X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2014,6,17]]}}}