Familial cramp due to potassium-aggravated myotonia. Issue 4 (1st October 1998)

• Record Type: Journal Article
• Authors: Orrell, Richard W; Jurkat-Rott, Karin; Lehmann-Horn, Frank; Lane, Russell J M
• Is Part Of: Journal of neurology, neurosurgery and psychiatry. Volume 65:Issue 4(1998)
• Page Start: 569
• Page End: 572
• Publication Date: 1998-10-01
• Subjects: cramp -- sodium channel disease -- potassium-aggravated myotonia; Neurology -- Periodicals; Nervous system -- Surgery -- Periodicals; Psychiatry -- Periodicals; 616.8
• DOI: 10.1136/jnnp.65.4.569
• Languages: English
• ISSNs: 0022-3050

Abstract

Abstract : Clinical, electrophysiological, and molecular genetic features were investigated in two patients from a family a with dominantly inherited myotonic disease, characterised by painful cramps, stiffness without weakness, fluctuation of symptoms, and cold sensitivity. A reduction in amplitude of the compound muscle action potential was demonstrated on cooling and administration of potassium, although no clinical exacerbation was seen. A heterozygote mutation Val1589Met was identified in the α-subunit of the skeletal muscle sodium channel gene in both patients, consistent with the diagnosis of potassium-aggravated myotonia. The phenotype in this family is much milder than that previously described in another family with a mutation at this site.