By Casey Carl

Retinal Dysplasia/Oculoskeletal Dysplasia 1 (RD/OSD1): A Preventable Inherited Disease of the Labrador Retriever

Thanks to our loyal and dedicated clients, Paw Print Genetics continues to increase test offerings in 2015! To start our year off right, we released DNA profiling and parentage testing, seven long-awaited canine coat color tests, and four tests for other specific traits of the hair coat and tail. In addition, Paw Print Genetics continues to expand upon the largest canine inherited disease testing menu in North America by releasing 10 new inherited disease tests. One newly added test that will make many Labrador retriever owners happy is the test for an inherited disease known as retinal dysplasia or the more apt term, oculoskeletal dysplasia (often written as retinal dysplasia/oculoskeletal dysplasia 1 or abbreviated, RD/OSD 1). In March of 2014, RD/OSD 1 became a little more personal for Paw Print Genetics when we had the honor of meeting Frank, an adorable, blind RD/OSD 1 affected Labrador retriever living at the Double J Dog ranch in Hauser Lake, Idaho. We are excited to launch a test that allows breeders of sweet dogs like Frank to produce puppies free of this severe and challenging disorder!

RD/OSD 1 is a genetic disease of collagen caused by a mutation in the COL9A3 gene. Affected dogs are typically identified before 2 months of age with a combination of marked skeletal malformation (particularly in the front limbs) and severe vision deficits. As these puppies grow, forelimb dwarfism becomes evident and the forelimbs become severely bowed resulting in abnormal joint development of the elbow putting dogs at risk for early-onset arthritis. Owners of affected dogs may also notice abnormal, dome-shaped skulls. The ocular abnormalities of affected dogs range from mild to severe. Abnormal development of the retina, retinal detachment, and cataracts are common and frequently result in blindness or severe vision deficits. Unfortunately, there is no cure for RD/OSD1.

RD/OSD 1 is inherited in a recessive fashion meaning that a dog must inherit two copies of the COL9A3 mutation (one from each parent) in order to develop the disease. Dogs inheriting only one copy of the mutation are considered “carriers” of the mutation and will not develop the skeletal malformations of affected dogs. However some, but not all, carrier dogs develop mild abnormalities of the retina including retinal folds and may have some mild vision deficits. In order to produce pups free of ANY abnormalities related to this mutation, it would be important to only breed dogs that have not inherited the mutation. Labradors that have retinal folds on eye exam cannot be certified by CHIC (Canine Health Information Center) until they have tested normal for the RD/OSD 1 mutation.

Paw Print Genetics offers testing for RD/OSD 1 in the Labrador retriever, labradoodle, and Australian labradoodle to identify carriers of the associated mutation. If you have questions about how you can eliminate RD/OSD 1 from your Labrador breeding program or if you’d like to test for one of the other 14 inherited diseases of Labradors now offered by Paw Print Genetics, email us at moc.s1511006586citen1511006586egtni1511006586rpwap1511006586@sUks1511006586A1511006586 or call us at the laboratory (509-483-5950).