Craniomandibular osteopathy / CMO (SLC37A2-related) - Basset Hound

What does this test analyse?

This genetic test analyses the SLC37A2 c.1446+1G>A variant in the Basset Hound. The condition is known as craniomandibular osteopathy, CMO, Lion Jaw, jaw bone overgrowth, craniofacial hyperostosis and a Caffey-like bone growth disorder in young dogs.

SLC37A2 is involved in biological processes that support normal bone development and bone remodelling. The tested splice-site variant is expected to disrupt correct processing of the SLC37A2 transcript. This can lead to excessive bone formation in young dogs, especially around the mandible and other skull bones.

What does CMO mean for the dog?

CMO is a developmental skeletal disorder that usually becomes visible during growth. Typical signs include painful swelling of the jaw, difficulty opening the mouth, drooling, reduced appetite, fever and sometimes weight loss because eating becomes painful. Severity can differ between dogs because the variant acts in an autosomal dominant way with incomplete penetrance.

This means that one copy of the variant can cause CMO, but not every variant-positive dog develops equally clear signs. That is exactly why DNA information is useful: it reveals a hidden inherited predisposition before a dog is used for breeding.

Practical value of this test

This test gives breeders and veterinarians concrete information about a Basset Hound line in which CMO may occur.

• The result shows whether the dog carries no copy, one copy or two copies of the tested SLC37A2 variant.
• Breeders can identify variant-positive dogs and avoid combinations that unnecessarily increase the variant in the line.
• In young dogs with jaw pain, swelling or feeding problems, the result helps include CMO earlier as an inherited possibility.
• Because penetrance is incomplete, the result supports breeding risk assessment without relying only on visible signs.

Inheritance and interpretation

The variant follows autosomal dominant inheritance with incomplete penetrance. A dog with one variant copy can pass it to about half of its offspring. The visible severity can vary, but a variant-positive result is important for breeding selection, risk management and follow-up of young dogs.