Craniomandibular Osteopathy, CMO

 

Gene: SLC37A2

Transmission: Autosomal dominant, incomplete penetrance (complex genetics)

Mutations:

Terrier mutation: Substitution (splicing error), SLC37A2 gene; c.1332 C>T, exon15

Basset Hound mutation: Substitution (splicing error), SLC37A2 gene; c.1446+1 G>A

Medical system: Skeletal

Breeds: American Staffordshire Terrier/Amstaff, Australian Shepherd, Basset Hound, Beagle, Border Collie, Boston Terrier, Boxer, Cairn Terrier, Chihuahua, Coton de Tulear, Doberman Pinscher, French Bulldog, Lancashire Heeler, Miniature Pinscher, Pekingese, Pug, Scottish Terrier, West Highland White Terrier, Yorkshire Terrier

Age of onset of symptoms: from 4 to 8 months

Craniomandibular Osteopathy (CMO), also called Lion’s Jaw or Scotty Jaw, is a proliferative bone disease of young dogs that is seen in several terrier breeds.  Symptoms occur in the growth phase of adolescence, between 4 and 8 months of age and include swelling of the jaw, difficulty in opening the mouth, pain, lack of appetite and fever.  There is an excessive proliferation of bone tissue due to an inhibition of the bone resorption and remodeling that is necessary from normal bone growth.  Bony lesions occur on bones of the skull, especially on the jaw bone (mandible) and also the tympanic bulla.  Symptoms can resolve with time when the growth period is finished, usually after a year.  The genetics of this disease has been described both as autosomal recessive and as autosomal dominant with incomplete penetrance.  Although the SLC37A2 gene mutation makes an important genetic contribution to the disease, there are additional genetic factors that have not as yet been identified.  For example, a sub-group of terriers can be positive for CMO but negative for the SLC37A2 mutation, and CMO is described in the Deutsch Drahthaar breed of dogs where it is not caused by the SLC37A2 mutation.

 

References:
OMIA link: [2244-9615]

Donner J, Freyer J, Davison S, et al. (2023) Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs.  PLoS Genet. 19(2):e1010651. [pubmed/36848397]

Letko A, Leuthard F, Jagannathan V, et al. (2020) Whole genome sequencing indicates heterogeneity of hyperostotic disorders in dogs. Genes (Basel) 11:163.  [pubmed/32033218]

Hytomen MK, Arunilli M, Lappalainen AK, et al.  (2016)  Molecular characterization of three canine models of human rare bone diseases : Caffey, van den Ende-Gupta, and Raine Syndromes. Plos Genetics 12(5) :e1006037. [pubmed/27187611]

Vagt J, Distl O. (2018) Complex segregation analysis of craniomandibular osteopathy in Deutsch Drahthaar dogs.  The Veterinary Journal 231:30-32. [pubmed/29429484]