Inherited connective tissue disease of the Dachshund characterised by severe bone and dental fragility. It is caused by a mutation in SERPINH1, which encodes HSP47, a chaperone essential for type I collagen folding. Spontaneous, intrauterine or perinatal fractures appear, together with dental hypomineralisation (fragile, translucent teeth), blue-greyish sclera and, occasionally, hypotonia and neonatal deaths. It is a natural model of human osteogenesis imperfecta and shares a molecular basis with some human recessive forms.

Dachshund, with cases in short-haired and wire-haired coats; the carrier frequency by country is not consolidated in the indexed literature (limited data).

- Spontaneous and intrauterine or perinatal fractures\n- Fragile, translucent teeth with thin dentine and abnormal tubules\n- Blue-greyish sclera\n- Joint hyperlaxity\n- Low radiographic bone density and superficial trabeculation\n- Possible abortions, stillbirths or puppies that fail to thrive

Canine osteogenesis imperfecta was described clinically and pathologically in the late 1990s. Drögemüller et al. (2009) identified the causal variant SERPINH1 c.977C>T (p.L326P) in homozygosis in the Dachshund, and Lindert et al. (2015) confirmed intracellular retention of procollagen, reticulum stress and altered cross-linking.

- Genotype breeding animals before mating\n- Do not cross two carriers: 25 % of homozygotes affected\n- A carrier can be crossed with a clear dog; offspring intended for breeding must be tested\n- After a confirmed case, do not repeat the parental mating and inform the buyer of the status\n- Consider control radiographs in litters from at-risk lines, without replacing the genetic test

Differential diagnosis with other bone dysplasias and with trauma. Bone biopsy shows scarce trabeculation and absence of mature bone; molecular study confirms. HSP47 is a collagen chaperone; the canine variant is a model of human recessive forms caused by SERPINH1. Other canine OIs caused by COL1A1 and COL1A2 exist in other breeds, with a different inheritance.

1. Drögemüller C et al. 2009, mutación missense en SERPINH1 en Teckels con osteogénesis imperfecta (PMID 19629171)
2. Lindert U et al. 2015, consecuencias moleculares de la mutación SERPINH1/HSP47 en el modelo canino de osteogénesis imperfecta (PMID 26004778)
3. OMIA:001821 Osteogénesis imperfecta (SERPINH1)