Background
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.
Age
Symptoms will develop at a young age. Within a few hours to a maximum of several weeks after birth, the characteristics that go with these genetic effects will become visible.
Throughput
Normally the result can be expected within 15 working days. This turn-around-time starts when both the sample and the fully filled-out and signed submission form have been received.
Location of disease or trait
This disease mainly affects vision, and may result in blindness.
Breed dependence
This DNA test is available for the following breeds: Labrador Retriever.
Sample type
For this DNA test we accept the following materials: Blood EDTA, Swab, Blood Heparin, Semen, Tissue. Please contact PharmaDNA if you wish to submit other material as listed.
Result
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 also 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 also become ill.
Inheritance
This genetic factor is inherited in an autosomal, dominant, mode. This means, that the individual can be free of the mutation (homozygote normal), affected (homozygous affected) or carrier (heterozygous affected). Both carriers and affected individuals will show symptoms of the mutation.
Severity of Disease
-
