|Other Names:||Brittle bone disease, OI|
|Mutation:||chr14:19918265-19918268: 4 bp deletion (del CTGA), 9 bp insertion (ins TGTCATTGG)|
Osteogenesis imperfecta (OI) is an inherited Collagen disorder affecting dogs. Affected dogs typically present between 3 to 4 weeks of age with pain, lameness and fractures. OI is caused by a defect is in the way collagen is made. Because collagen is an important component of bone, bones of affected animals are thinner than normal, fracture easily and do not heal properly. Other features of the disorder include loose joints and brittle teeth. Affected puppies may die shortly after birth and be smaller than littermates. Because of the severity of the disease, pups with OI are usually euthanized by 3 months of age.
Genetic testing of the COL1A2 gene will reliably determine whether a dog is a genetic Carrier of osteogenesis imperfecta (beagle type). Osteogenesis imperfecta (beagle type) is inherited in an Autosomal Dominant manner in dogs meaning that they only need to inherit one copy of the mutated gene to develop the disease. Each pup that is born to a parent carrying one copy of the Mutation has a 50% chance of inheriting one copy of the COL1A2 gene mutation and developing the disease. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers is not recommended. Dogs that are not carriers of the mutation have no increased risk of having affected pups.
There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.
- Campbell BG, Wootton JA, Macleod JN, Minor RR. Canine COL1A2 mutation resulting in C-terminal truncation of pro-alpha2(I) and severe osteogenesis imperfecta. J Bone Miner Res. 2001 Jun; 16(6):1147-53. [PubMed: 11393792]