Progressive Retinal Atrophy (PRA) is a family of inherited progressive degenerative eye diseases affecting the retina which ultimately result in blindness. Typically the first symptom of PRA is night blindness followed by increased reflectivity of the fundus or a “green sheen” to the eyes when viewed in dim light. There are several recognized forms of PRA and Mastiffs now have a DNA gene test available to them! The PRA DNA tests enable breeders to send in a blood sample and determine whether or not a dog has PRA or is clear (does not have the gene mutation for PRA) before the dog is old enough to develop symptoms. This also allows breeders to plan their breedings to avoid producing any pups that will be affected by PRA.
The Mastiff Club of America Eye Disorders Sub-Committee's DNA Testing Recommendations
It is the recommendation of the MCOA Health Committee Eye Disorders Sub-Committee that prior to breeding, both the sire and dam are proven to be free of the dominant Mastiff PRA gene mutation either by DNA test or by having both parents proven free of the gene. For example, a Mastiff is proven clear of the PRA gene if:
- both parents are DNA tested clear
- or, both of the sire’s parents are DNA tested clear and the dam is DNA tested clear
- or, both of the dam’s parents are DNA tested clear and the sire is DNA tested clear
- or, all four grandparents are DNA tested clear
- Animal Genetics
- Genetic Technologies (Australia)
- Paw Print Genetics
- Wisdom Health
The History Behind the Mastiff PRA DNA Test
The MCOA PRA Committee, along with Dr. Acland, undertook a breeding study to help determine the mode of inheritance of PRA in Mastiffs. The Study was based on a proposal written by Dr. Acland for the MCOA and peer reviewed by well known and respected PhDs in the field of DNA research. In simple terms, the Study involved breeding a PRA affected Mastiff to a Beagle mix from Dr. Acland’s kennel that was known not to carry any PRA genes. The pups from this litter were placed in good homes with owners who made a commitment to the research and were willing to have Electroretinagrams (ERGs) done every six months until the pups were two years old. If any of the pups developed PRA, then PRA in Mastiffs would be proven to be dominant – which is the case as two Meagles out of six developed PRA.
In June 2001, OptiGen informed the MCOA PRA Research Committee that the Mastiff PRA DNA test was ready to go. OptiGen immediately started testing Mastiffs as soon as they made the announcement that the test was commercially available.
Blind dog resources and information: http://www.blinddogs.net/