Craniomandibular Osteopathy in Dogs

Category: Bone & Joint
Inheritance: Multifactorial
Breeds documented: 3
Published sources: 5

Overview

Abnormal bone growth around the lower jaw and the bony structures near the ears can make eating painful for a growing puppy. In craniomandibular osteopathy, normal bone is repeatedly replaced by immature bone. The jaw may become swollen, and severe cases can limit how far the mouth opens. The extra bone growth generally settles as the dog matures.

Signs to watch for

A swollen, painful lower jaw
Pain when moving the jaw
Difficulty opening the mouth or picking up food
Heavy drooling
Weight loss

Usually seen in growing dogs between 3 and 12 months of age.

When to get help Book a vet visit for mouth pain, difficulty eating or unexplained weight loss.

Diagnosis and tests

Vets confirm the condition with X-rays of the head and jaw. The images show irregular new bone, often affecting both sides of the lower jaw and the bony structures near the ears. The jaw joint may also be involved, helping explain a restricted mouth opening.

Breeds with documented risk

3 breeds

By breed size

3 Small

West Highland White TerrierSmall · Terrier Group
Scottish TerrierSmall · Terrier Group
Cairn TerrierSmall · Terrier Group

Inheritance

This condition has more than one known form, and different breeds inherit it in different ways. The sources list the form found in each breed.

Multifactorial
Several genes and the environment together set the risk. Diet, growth rate, weight and exercise can all play a part. There is no single DNA test. Screening the parents (for example hip or elbow scores) and choosing from lines with good results lowers the risk, but does not remove it.
As stated by OMIA
Autosomal recessive
West Highland White Terrier
A dog is affected only if it inherits two copies of the gene variant, one from each parent. A dog with one copy is a carrier: usually healthy, but able to pass the variant on. When two carriers are bred, on average one puppy in four is affected. A DNA test can tell clear, carrier and at-risk dogs apart.
As stated by OMIA
Autosomal dominant, incomplete penetrance
West Highland White Terrier, Cairn Terrier, Scottish Terrier
One copy can be enough, but not every dog with the variant develops the condition, and severity can vary. A DNA result shows risk, not certainty.
As stated by OMIA

We've gathered what published sources say about this condition, so you can talk it through with your vet. It isn't veterinary advice: you and your vet know your dog best.