Craniomandibular Osteopathy (CMO) in Dogs

Craniomandibuläre Osteopathie
A typical radiograph of the skull of a CMO-affected dog: new bone formation is located along the corpus mandibulae (arrows).


Craniomandibular osteopathy (CMO) is a genetic bone disease of the cranial bones and the lower jaw. The very painful disease starts at the age of about 4-7 months, progresses in episodes, and usually self-heals without consequences. For a long time, only a radiological examination could be used for diagnosis. This hereditary disorder has previously been described in various dog breeds. The identification of the gene variant responsible for CMO and subsequent development of genetic tests can help to avoid breeding affected dogs and enable earlier diagnosis. In our research, we identified the causative gene and several causative variants for CMO in dogs.

One mutation we discovered explains CMO cases in three terrier breeds (West Highland White, Scottish, and Cairn Terriers) and is inherited in an autosomal dominant manner with incomplete penetrance. Not all dogs carrying this mutation develop CMO visibly or with equal severity. However, dogs that are homozygous for the mutation, i.e. have two copies of the variant, have a comparatively high risk of developing CMO. Dogs that are heterozygous for the mutation and therefore only carry one variant copy, on the other hand, rarely develop the disease.

Our studies have demonstrated allelic and genetic heterogeneity of CMO in dogs.

Breeds studied so far

  • American Staffordshire Terrier
  • Australian Terrier
  • Basset Hound
  • Cairn Terrier
  • Curly Coated Retriever
  • German Wirehaired Pointer
  • Old English Sheepdog
  • Scottish Terrier
  • Weimaraner
  • West Highland White Terrier