Retinal Dysplasia (retinal folds, RD) is a common clinical observation in many dog breeds. Since many retinal folds are benign and of unknown heritability, veterinary ophthalmologists will often advise that breeding dogs with RD is an acceptable option. However in a few breeds RD is accompanied with a serious inherited syndrome called OSD (OculoSkeletal Dysplasia). OSD is a severe condition in which the dogs show a variety of skeletal malformations, including shortened limbs (dwarfism), and blindness at an early age; the blindness results from a generalized malformation of the retina.
Test specific information
It has been known for many years that carriers of OSD often have retinal dysplasia-retinal folds. Furthermore, when two carriers of OSD are bred, a quarter of their litter, on average, are dwarfed and blind. This inheritance pattern, as well as the equal distribution of the disease in males and females, indicated that there was a single gene responsible for the disease and that it was autosomal in inheritance. However, unlike many other DNA tests, the OSD mutation is not simple recessive.
Because the carriers typically show symptoms of RD, the interpret this as a mild or partial expression of OSD in the Carrier.
Two copies of the OSD mutation produce a severe expression of OSD, recognized by dwarfism and blindness. This type of inheritance is known as autosomal dominant with incomplete penetrance, or incomplete dominance.
This test is performed by OPTIGEN.
The disease may show itself on different ages, in which it cannot be estimated when the first symptoms may show themselves. Differences may exist between littermates, and between breeds.
Turn Around Time
The turn-around-time of a test depends to a large extent on the logistics of sample transportation to the laboratory. After receiving the sample at the test location, you can normally expect the result within 10 working days. A longer delivery time applies to tests carried out by a Partner Lab.
Location of disease or trait
This disease mainly affects vision, and may result in blindness.
This DNA test is available for the following breeds: Samoyed. Additional information is available in the Frequently Asked Questions (FAQ).
For this DNA test we accept the following materials: Blood Heparin, Blood EDTA, Tissue, Swab, Semen. Please contact Dr. Van Haeringen Laboratorium if you wish to submit other material as listed.
An animal can be free and has in that situation two healthy alleles. When used in breeding this animal will not become ill due to the disease. It cannot spread the disease in the population.
An animal can be carrier and has in that situation one healthy and one disease allele. When used in breeding 50 percent of the offspring will receive the disease allele. Carriers will not become ill.
An animal can be affected and has in that situation two disease alleles. When used in breeding all offspring will also receive the disease allele. Affected will become ill.
This genetic factor is inherited in an autosomal, recessive, mode. This means, that the individual can be free of the disease (homozygote normal), affected (homozygous affected) or carrier (heterozygous).
Carriers may spread the mutation in a population without showing symptoms themselves. Because of this, it is extremely important to identify carriers correctly to prevent spreading of a mutation.
Severity of Disease