Overview
A number of tests are available for the Yorkshire Terrier. Two or more of these tests purchased as part of this bundle will be discounted.
- Chondrodysplasia (CDPA) associated with the FGF4 -18 retrogene insertion
- Chondrodystrophy (CDDY) with risk of IVDD associated with the FGF4-12 retrogene insertion.
- Primary Lens Luxation associated with the ADAMTS17 gene
- Progressive Retinal Atrophy associated with the PRCD gene
Chondrodysplasia (CDPA)
Chondrodysplasia (CDPA) is shortened long bones, resulting in dogs with short legs.
A partial copy of the FGF4 gene has been inserted (FGF4-18, a retrogene insertion) on chromosome 18 and is associated with CDPA. Evidence that suggests that any dog with one or two copies of FGF4-18 will have short legs. Unlike CDDY, CDPA is not associated with any disease.
Chondrodystrophy (CDDY) with risk of IVDD
Chondrodystrophy (CDDY) in dogs is defined by dysplastic (abnormal), shorted long bones (short legs) and premature degeneration and calcification of intervertebral discs. Chondrodystrophic breeds are prone to a type of disc degeneration called chondroid metaplasia, where the discs become hardened and less able to flex with movement and therefore more prone to bulging or rupture i.e. Intervertebral Disk Disease (IVDD). The calcified inner disc material also puts pressure on the spinal cord, causing pain and damage to the nerves running through the spinal cord. Dogs may suffer from severe pain, inability to urinate or defecate, paralysis and even death. Many affected dogs are treated by surgically removing the prolapsed disc.
A partial copy of the FGF4 gene has been inserted (FGF4-12, a retrogene insertion) on chromosome 12 and is associated with CDDY. Evidence that suggests that any dog with one or two copies of FGF4-12 will be affected with CDDY, will have short legs and will be predisposed to IVDD. However, not all dogs with FGF4-12 will go on to develop IVDD.
Primary Lens Luxation
Primary lens luxation (PLL) is a painful and potentially blinding inherited eye disease that typically affects dogs between 3 and 8 years of age and in many breeds is caused by a single nucleotide substitution in the ADAMTS17 gene.
PLL is the term given to the spontaneous displacement or movement of the lens from its normal position within the eye, as a result of rupture of the lens zonules that hold the lens in its normal position. The zonules are a network of tiny fibres that attach the edge of the lens to the ciliary muscle that circles the eye, in the same way that springs attach a trampoline to its frame. Following zonule rupture the lens usually moves to the anterior chamber at the front to the eye where it can cause damage and rapid onset glaucoma by obstructing the drainage of fluid out of the eye resulting in an increase of pressure within the eye. Glaucoma can cause irreversible vision loss if not treated quickly. PLL is invariably bilateral (occurs in both eyes), although a period of several weeks or months might separate luxation of the two lenses. Clinical signs of PLL include sudden onset of eye pain, clouding of the cornea (the front of the eye will look blue), redness of the “white” of the eye and a reluctance to exercise. PLL should be considered an emergency and veterinary assistance sought immediately.
Progressive Retinal Atrophy (PRCD)
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Progressive retinal atrophy (PRA) is the most common form of inherited disease affecting the retina in dogs. Genetically different forms of PRA, caused by mutations in different genes, affect many breeds of dog with each form usually affecting one or a small number of breeds. PRA is characterised by progressive degeneration of the retina at the back of the eye and leads to vision loss and blindness.
Progressive Rod Cone Degeneration (PRCD) is a form of PRA and was one of the first PRAs for which a genetic variant was identified. PRCD is different than most forms of PRA in that the variant has been found in a large number and diverse range of breeds.
