Graphic: corner
spacer
Graphic: corner
spacer spacer
nav left edge
nav right edge
spacer

Breeding Strategies for prcd-PRA Test:

This table highlights all the desirable breedings that include at least one Normal/Clear parent. All other breedings are at risk of producing Affected pups with an extremely high probability of developing prcd during their lifetime. However, all dogs can be bred safely. It isn't necessary - or even desirable - to remove dogs from the breeding population. But when choosing pups to retain as potential breeding stock, it is important to select for Normal/Clear dogs and select against Affected dogs.

Expected results for breeding strategies using the OptiGen prcd test
Parent 1
Status
Parent 2 Status
Normal/Clear Carrier Affected
Normal/Clear All = Normal/Clear 1/2 = Normal/Clear
1/2 = Carrier
All = Carrier
Carrier 1/2 = Normal/Clear
1/2 = Carrier
1/4 = Normal/Clear
1/2 = Carrier
1/4 = Affected
1/2 = Carrier
1/2 = Affected
Affected All = Carrier 1/2 = Carrier
1/2 = Affected
All = Affected
 

Benefits & Limits to All Genetic Testing:

The benefits of genetic disease testing are clear. With informed breeding practices, breeders immediately can avoid producing affected pups, yet use any dog in their program regardless of genetic disease status. And since genetic testing can be done at any age, each dog’s genetic status can be known before clinical disease signs are recognized. Over several generations of selection away from the disease gene, breeders can even eliminate a disease gene completely from their line.

BUT, there are basic limits for any and all DNA genetic tests. Whether a test is mutation-based or marker-based, it identifies only the specific mutation being tested or the association between a specific marker set and the disease. For example, a mutation test detects one specific mutation in one specific gene. If there are several different mutations or several different genes that can cause the same condition, one must discover and then test for each mutation and each gene. Likewise, a marker test uses one marker or set of markers to define a specific condition. If the condition is associated with several different marker combinations, one must discover and then test for each marker combination. It can be difficult or even impossible to know how many mutations or how many marker sets exist in all the members of a specific breed. As more and more dogs are tested, previously unknown variations may come to light.

In the case of PRA, also keep in mind that not all retinal disease is PRA and not all PRA is the form currently detectable in your breed. Accurate diagnosis is essential. A dog can test as normal or carrier, yet be affected by a different type of PRA. Although more than one type of retinal degeneration probably occurs in every breed, by far the most common type of PRA for your breed is the type currently being tested by OptiGen.

Additional Points:

  • The OptiGen prcd test can be done reliably at any age – even in young pups, and the result will be the same at any age, and will be the same whenever it is repeated.
  • Since most breeds are affected with other inherited eye diseases, we recommend that yearly eye examinations by a board certified veterinary ophthalmologist be continued, for example, through the CERF program in the U.S. or similar program elsewhere. However, a normal exam in a young dog cannot rule out PRA at a later age. To establish PRA affected status by ERG, it is necessary that a full diagnostic protocol be done with dogs under anesthesia or heavy sedation, and that the rod and cone contributions of the ERG be separately evaluated.
  • Tallies of test results are updated and provided quarterly to national breed clubs, at their request.

spacer
Graphic: footer bar left
OptiGen®, LLC · Cornell Business & Technology Park · 767 Warren Road, Suite 300 · Ithaca, New York 14850
Tel: 607 257 0301 · Fax: 607 257 0353 · email: genetest@optigen.com or optigen@clarityconnect.com
Graphic: footer bar right
spacer spacer
spacer
spacer
spacer