Congenital Myasthenic Syndrome, CMS

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.

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

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

Talk to your vet about your dog’s CMS result so you can plan appropriate monitoring and care.

Avoid intense or prolonged exercise, as overexertion can worsen weakness or fatigue.

Provide a calm, stable routine with gentle activity to help maintain mobility and prevent stress.

With careful management and regular check-ins, many dogs with CMS can live comfortable lives.

This mutation was first described in a Jack Russell Terrier.

Penetrance: 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

CHRNE

Inheritance type

recessive

Clinical category

Neuromuscular

Citations

1. Steffen et al 2015

• Russell Terrier
• Russell-type Terrier
• Jack Russell Terrier
• Parson Russell Terrier