Craniomandibular Osteopathy, CMO


Craniomandibular Osteopathy (CMO) affects multiple bones in young dogs. The most prominent sign in affected puppies is painful jaw swelling, leading to difficulty opening the mouth. It may occasionally occur on the bones of the legs. Signs of CMO usually resolve with time, when a puppy's growth period is finished.

  • Signs and symptoms

    Affected dogs may have a painful swelling of the jaw and consequent signs of discomfort (difficulty opening the mouth, salivation, lack of appetite, and difficulty swallowing). In addition, inflammation often results in fever during the early phase.

    Clinical signs begin around four months old and may continue up to 12 months.

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  • Diagnosis

    A diagnosis is made based on X-rays, clinical signs, and genetic testing. Typically, lesions occur on both sides of the skull, but asymmetric changes are possible. Computed tomography (CT) may be helpful for further evaluation.

  • Treatment

    All clinical signs usually resolve with time when regular bone growth is complete.

  • What to do if your dog is at risk


    • Supportive care with anti-inflammatories may improve signs of CMO and help in pain management.
    • Dietary modification (such as syringe or slurry feeding) may be needed to prevent malnutrition. Speak with your veterinarian regarding any dietary changes, especially in young puppies.

  • Genetic Information

    This variant was first described in the Basset Hound.

    This variant is inherited in a dominant manner, meaning that a dog requires at least one copy of the variant to show signs of CMO.

    Gene names:

    SLC37A2 Intron 16 ‐ chr

    Inheritance type:


  • Breeds affected

    This health condition affects the following breeds

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