Disease overview

Myotonia is a congenital muscular condition that is characterized by muscle stiffness and contraction. This is due to a chloride channel disorder, which causes delayed relaxation after muscle contraction.

Gene name

CLCN1

Inheritance

Autosomal recessive

Signs and symptoms

Affected dogs exhibit a stiff gait and muscle rigidity. This typically occurs after resting, and can subside after normal exercise. The tongue muscle may be affected, which can lead to a protruding tongue. Involuntary muscle contractions can be affected, causing difficulty swallowing or regurgitation after eating.

How is it diagnosed

A veterinarian will conduct a thorough exam, including a review of health history and any clinical signs. A muscle biopsy may be indicated. Genetic testing is necessary to determine if there is an underlying genetic cause, which can assist veterinarians with diagnosis and help breeders identify affected and carrier dogs.

Breeds at higher risk

, , , , , , , , ,

Citations

Rodrigues DJ, Damasceno AD, Araújo CET, Torelli SR, Fonseca LGH, Delfiol DJZ, Oliveira-Filho JP, Araújo-Júnior JP, Borges AS. Hereditary myotonia in American Bulldog associated with a novel frameshift mutation in the CLCN1 gene. Neuromuscul Disord. 2020 Dec;30(12):991-998. doi: 10.1016/j.nmd.2020.10.007. Epub 2020 Oct 24. PMID: 33246886.

Quitt PR, Hytönen MK, Matiasek K, Rosati M, Fischer A, Lohi H. Myotonia congenita in a Labrador Retriever with truncated CLCN1. Neuromuscul Disord. 2018 Jul;28(7):597-605. doi: 10.1016/j.nmd.2018.05.002. Epub 2018 Jun 19. PMID: 29934119.

Lobetti RG. Myotonia congenita in a Jack Russell terrier. J S Afr Vet Assoc. 2009 Jun;80(2):106-7. doi: 10.4102/jsava.v80i2.181. PMID: 19831273.

Finnigan DF, Hanna WJ, Poma R, Bendall AJ. A novel mutation of the CLCN1 gene associated with myotonia hereditaria in an Australian cattle dog. J Vet Intern Med. 2007 May-Jun;21(3):458-63. doi: 10.1892/0891-6640(2007)21[458:anmotc]2.0.co;2. PMID: 17552451.

Bhalerao DP, Rajpurohit Y, Vite CH, Giger U. Detection of a genetic mutation for myotonia congenita among Miniature Schnauzers and identification of a common carrier ancestor. Am J Vet Res. 2002 Oct;63(10):1443-7. doi: 10.2460/ajvr.2002.63.1443. Erratum in: Am J Vet Res. 2003 Jan;64(1):25. PMID: 12371774.

Smith BF, Braund KG, Steiss JE, Simpson ST, Cox NR, Sorjonen DC. Possible adult onset myotonic dystrophy in a boxer. J Vet Intern Med. 1998 Mar-Apr;12(2):120. PMID: 9560770.

Hill SL, Shelton GD, Lenehan TM. Myotonia in a cocker spaniel. J Am Anim Hosp Assoc. 1995 Nov-Dec;31(6):506-9. doi: 10.5326/15473317-31-6-506. PMID: 8581546.

Shores A, Redding RW, Braund KG, Simpson ST. Myotonia congenita in a Chow Chow pup. J Am Vet Med Assoc. 1986 Mar 1;188(5):532-3. PMID: 3957761.

Shires PK, Nafe LA, Hulse DA. Myotonia in a Staffordshire terrier. J Am Vet Med Assoc. 1983 Jul 15;183(2):229-32. PMID: 6885599.

Disclaimer

Disease diagnosis and treatment should always be performed by a veterinarian. The following information is for educational purposes only.