Clinical signs of the disease appear at a young age. Affected puppies show progressive muscular weakness, respiratory problems, and have cardiomyopathy. The prognosis of the disease is poor.

Glucocorticoid therapy and dantrolene therapy may provide temporary improvement. However, because of the severity of the clinical signs, affected puppies are usually euthanized at a young age on welfare grounds.

There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.

This disorder is X-linked recessive, meaning the genetic variant is found on the X chromosome. Given males only have one X chromosome, a single affected copy will increase the risk of being diagnosed with the disorder. Females typically require two copies to be at an elevated risk. Use of dogs with one or two copies of the variant is not recommended for breeding as there is a risk that the resulting litter will contain affected puppies. Please note: It is possible that clinical signs similar to the ones caused by this variant could develop due to a different genetic or clinical cause.