The onset of signs typically occurs at 1-2 weeks of age. A characteristic sign of hypomyelination is muscle tremor. The severity of the tremor can vary between individuals, however body tremors tend to worsen with activity (action tremor) and decline during rest. Affected dogs are able to walk, but they may have a "hopping-like movement of the hind legs. Affected puppies usually improve by 3-4 months of age, although some dogs may continue to exhibit a mild persistent tremor of the hind legs.

Treatment is supportive care and assistance with daily activities as needed 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 Hypomyelination mutation can be safely bred with a clear dog with no copies of the Hypomyelination mutation. About half of the puppies will have one copy (carriers) and half will have no copies of the Hypomyelination 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 Hypomyelination mutation could develop due to a different genetic or clinical cause.