Osteogenesis imperfecta (OI), known as brittle bone disease, is an inherited connective tissue disorder that causes bone fragility and fractures from minimal or spontaneous trauma. In the Golden Retriever, a form associated with a mutation in COL1A1 (type I collagen alpha-1) has been described, one of the chains of type I collagen, the most abundant structural protein of bone, tendons and skin. The molecular test detects the known variant.

Documented sporadically in the Golden Retriever; there are no verifiable population frequency estimates (limited data). Most of the described cases are diagnosed in the first months of life.

- Spontaneous fractures or fractures from minimal trauma
- Bone pain
- Skeletal deformities (bowed limbs, scoliosis)
- Growth retardation (small stature)
- Dentinogenesis imperfecta (translucent or yellowish teeth), variable
- Ligamentous hyperlaxity and thin skin (variable)

Canine OI was described clinically in three dogs by Campbell et al. (1997). In 2000, the same group identified in a Golden Retriever puppy with multiple fractures and dentinogenesis imperfecta the causal mutation in COL1A1: a transition that changes glycine to alanine in the triple helix (published as c.1276G>C, p.Gly208Ala). In 2001 they also described a truncating mutation in COL1A2 in a Beagle with severe OI. Other canine forms are due to mutations in SERPINH1 (teckel) and in COL1A2, which demonstrates the genetic heterogeneity of canine OI.

- Do not breed affected animals.
- Since inheritance is dominant, review the pedigree and test relatives before using them as breeding animals.
- Avoid matings between lines with a history of OI.
- Keep a record of genetic results in the pedigree.

The diagnosis is suspected by recurrent fractures, deformities and family history, and is confirmed with the genetic test. There is no cure: management is supportive (analgesia, treatment of fractures, physiotherapy and pain control). The prognosis depends on severity; mild cases can have a relatively normal life and severe cases require intensive management. It is important not to confuse the COL1A1 form with OI due to COL1A2 or SERPINH1, which require specific tests.

1. Campbell BG, Wootton JA, Krook L, DeMarco JA, Minor RR. Clinical signs and diagnosis of osteogenesis imperfecta in three dogs. J Am Vet Med Assoc. 1997;211(2):183-187. PMID: 9227748.
2. Campbell BG, Wootton JA, MacLeod JN, Minor RR. Sequence of normal canine COL1A1 cDNA and identification of a heterozygous alpha1(I) collagen Gly208Ala mutation in a severe case of canine osteogenesis imperfecta. Arch Biochem Biophys. 2000;384(1):37-46. PMID: 11147834.
3. 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;16(6):1147-1153. PMID: 11393792.
4. Drögemüller C, Becker D, Brunner A, et al. A missense mutation in the SERPINH1 gene in Dachshunds with osteogenesis imperfecta. PLoS Genet. 2009;5(7):e1000579. PMID: 19629171.
5. OMIA:002126-9615. Osteogenesis imperfecta, type III, COL1A1-related in Canis lupus familiaris. https://omia.org/OMIA002126/9615/