Clinical signs of this disorder are present from birth. Affected dogs are smaller in size than their littermates. Affected dogs also have a broad skull, wide-set slanted eyes, and skin that appears thick and tight. The disorder is characterized by extremely limited joint mobility and short digits that causes the dogs to walk upright, often on their tip-toes. Other characteristics of the disorder include a high-pitched bark and an exceptionally exuberant temperament. Dogs with MLS typically have a normal life span, but commonly develop painful arthritis. The clinical signs usually stabilize by 1 year of age.

Treatment is pain management, supportive care, and symptomatic depending on the severity of the dog's clinical signs.

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 disease is autosomal recessive meaning that two copies of the mutation are needed for disease signs to occur. A carrier dog with one copy of the MLS mutation can be safely bred with a clear dog with no copies of the MLS mutation. About half of the puppies will have one copy (carriers) and half will have no copies of the MLS mutation. Puppies in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected puppies. Please note: It is possible that disease signs similar to the ones caused by the MLS mutation could develop due to a different genetic or clinical cause.