Congenital Myasthenic Syndrome, CMS


This is a disease characterized by episodes of severe exercise intolerance and weakness.

  • Signs and symptoms

    Affected puppies can usually play or run for up to a half hour, after which their strides get progressively shorter and the dog collapses. After resting, the puppy appears normal again.

    Signs first appear in puppies, typically starting at 6 weeks of age.

    Uncover health risks with Embark

    Embark Breed + Health Test

    Original price:


    Sale price:



    Embark for Breeders Dog DNA Test

    $129 - $159


  • Diagnosis

    Genetic testing, blood work, neurological tests, and clinical signs can be used to diagnose this condition.

  • Treatment

    CMS is a lifelong condition and affected puppies may become refractory to medication used to help treat the acquired form of this condition.

  • What to do if your dog is at risk


    • Minimizing intense exercise may help reduce clinical signs. Please follow the recommendations from your veterinarian.

  • Genetic Information

    This mutation was first described in a Jack Russell Terrier.

    This disease is inherited in an autosomal recessive manner, meaning that affected dogs must have two copies of the mutation to show clinical signs.

    Gene names:

    CHRNE ‐ chr

    Inheritance type:


  • Breeds affected

    This health condition affects the following breeds

Learn about your dog’s unique genetic health

Dog owners

Breed identification, health and trait insights, personalized care recommendations, and the world’s first canine relative finder—all in one leading dog DNA test.

Learn about the report for dog owners
Shop the test
Breeding programs

Embark’s test for breeding programs is one comprehensive DNA test designed with your needs in mind.

Learn about the report for breeders
Shop the test