Researchers at the University of Helsinki, UC Davis and the University of Jyväskylä have discovered that the gene RBP4 for canine congenital eye disease is passed from the mother to the puppies in the womb.
The researchers have discovered that this recessive gene, which blocks the developing eyes of puppies from getting vitamin A, causes blindness. In order for the disease to occur, both the mother and puppy must have the mutated gene, which is why all puppies are not born blind.
It has also been determined that the RPB4 gene may be related to human MAC disease. So again, understanding canine diseases may lead to cures for humans.
An Irish Soft-coated Wheaten Terrier, Photo: Lohi Research Group
The good news is that researchers have developed a DNA test that can identify those dogs that carry the gene. This will help both veterinarians and breeders control and hopefully eradicate blindness in this breed.
Over the past three years, veterinarians have continued to work with blindness in dogs. They have succeeded in curing X-linked retinitis pigmentosa when caught early. XLRP causes gradual vision loss starting at a very young age in dogs, often as early as five weeks of age. It is an inherited retinal disease.
Continuing the research using the same techniques, the researchers found that the gene therapy helped dogs at 12 weeks of age (mid-stage disease) when about 40% of the eye’s photoreceptor cells were dead and then at 26 weeks of age (late-stage) when 50 – 60% of the cells were dead. What the researchers found was that they were able to halt the degeneration of the photoreceptor cells in the treated area.
A few years ago, a team from the University of Pennsylvania announced that they had cured X-linked retinitis pigmentosa, a blinding retinal disease, in dogs. Now they’ve shown that they can cure the canine disease over the long term, even when the treatment is given after half or more of the affected photoreceptor cells have been destroyed.
To date, dogs have maintained their vision for over two years after treatment. This is very exciting because humans suffer from the same type of blindness. With that in mind, researchers are already examining human patients to determine how to treat their blindness and who might qualify for future treatments.
Again, man’s best friend is offering hope to humans who suffer from this type of cell death that causes blindness. Since this is an inherited disease, breeders should have their dogs examined by a certified canine ophthalmologist and register their dogs with the Canine Eye Registration Foundation, CERF. http://www.tctc.com/~maplerg/cerf-.htm This will help researchers continue to develop cures for blindness as well as prevent the breeding of dogs who have this inherited disease.
If you have a blind dog or are willing to adopt one, contact www.blinddogrescue.com