Myotonia Congenita

Affected puppies have prolonged muscle contractions, especially after resting. This leads to visibly appreciable muscle rigidity and a stiff, hopping gait. The tongue muscle is also often affected, causing affected dogs to have a characteristic protruding tongue. They may also have difficulty swallowing or regurgitating their food after eating due to involuntary muscle contractions.

Signs are first recognized in puppies.

Genetic testing, clinical signs, EMG, and muscle biopsy can be used to diagnose this disease.

There is no treatment currently for this condition, but physical therapy can be beneficial.

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

Signs such as muscle stiffness after rest often improve with gentle movement or warm-up activity.

Avoid sudden or strenuous exercise, and provide good traction at home to help your dog move safely.

Learning gentle stretching or physical therapy techniques from your vet may also help keep your dog comfortable and flexible.

This variant was first described in the Labrador Retriever.

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

Gene

CLCN1 Exon 19

Inheritance type

recessive

Clinical category

Muscular

Citations

1. Quitt et al 2018

• Labrador Retriever
• English Labrador Retriever