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Oculoskeletal Dysplasia (OSD) Samoyed Type
| Acronym: | OSD, RD |
| Gene: | COL9A2 |
| Mutation: | 1267bp deletion |
| Inheritance: | Autosomal recessive |
| Sample type: | CHS (Cheek Swab), WBE (Whole Blood EDTA) |
Genetics and characteristics
Oculoskeletal dysplasia Samoyed type is a hereditary disorder affecting the Samoyed dog breed. Retinal Dysplasia (RD), is observed in many dog breeds without any pathological consequence. However, in the Labrador Retriever breed as well as in Samoyeds, Retinal Folds can be associated with a more severe syndrome, Oculoskeletal Dysplasia (OSD). Affected dogs exhibit short-limbed dwarfism together with severe ocular defects including vitreous dysplasia, retinal detachment, and cataracts, and this phenotype is inherited as an autosomal recessive trait in both breeds. Obligate heterozygotes may exhibit a mild ocular phenotype that ranges from vitreal strands and or localized retinal dysplasia characterized by focal or multifocal retinal folds to large plaques of dysplastic retinal tissue but have a normal appendicular skeleton.
Dogs homozygous for either mutation can usually be recognized upon physical examination by an experienced veterinarian, particularly an experienced veterinary ophthalmologist, or an experienced veterinary orthopedist, and sometimes by experienced dog breeders. However, recognition of affected dogs is not sufficient to allow adequate selection pressure to be applied to significantly reduce the gene frequency of the mutation in the population.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (i.e. two pairs of healthy alleles). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
CARRIER |
Tested mutation was detected in animal with „carrier“ result. Animal tested as carrier has one wild-type and one mutation allele, it is in heterozygous state. It will not develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has two copies of mutation alleles affecting the gene. It is likely the animal will experience a genetic disorder due to this mutation.** It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
** Potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
Goldstein, O., Guyon, R., Kukekova, A., Kuznetsova, T.N., Pearce-Kelling, S.E., Johnson, J., Aguirre, G.D., and Acland, G.M. (2010). COL9A2 and COL9A3 mutations in canine autosomal recessive oculoskeletal dysplasia. Mamm. Genome 21, 398–408.