Congenital Myasthenic Syndrome (Jack Russell Terrier Type)

Test Overview:

Characteristics of congenital myasthenic syndrome Labrador retriever type are fatigable weakness of skeletal muscle. The weakness is a result of a defect in the synthesis of the neurotransmitter acetylcholine. Affected dogs are able to run normally for 5 to 30 minutes. Shortly after, dog’s strides become shorter and shorter, eventually resulting in a collapse. The dog recovers after some minutes of rest, and is able to walk or run for a certain period of time, before the symptoms’s reappearance. The first symptoms usually occur between 12 to 16 weeks of age, but it can vary between breeds. Congenital myasthenic syndrome symptoms appear similar to myasthenia gravis. But while myasthenia gravis is an autoimmune, CMS is an inherited disease caused by gene mutation.


Nervous system / Neurologic - Associated with the brain, spinal cord and nerves


Cholinergic receptor nicotinic epsilon subunit (CHRNE) on chromosome 5

Variant Detected:



Moderate. This disease can cause significant signs of discomfort and/or dysfunction in affected animals. It may involve relatively high treatment/management costs, and can sometimes reduce life expectancy.

Mode of Inheritance:

Autosomal Recessive

Research Citation(s):

Herder, V., Ciurkiewicz, M., Baumgärtner, W., Jagannathan, V., Leeb, T. (217) : Frame-shift variant in the CHRNE gene in a juvenile dog with suspected myasthenia gravis-like disease. Anim Genet 48:625, 2017. Pubmed reference: 28508416. DOI: 10.1111/age.12558.
Rinz CJ, et al. A CHRNE frameshift mutation causes congenital myasthenic syndrome in young Jack Russell Terriers. (2015) Neuromuscul Disord. 25(12):921-7

Associated Breed(s):

Australian Terrier, Jack Russell Terrier, Mixed Breed, Parson Russell Terrier,