In the years that followed the development of the PRA test for Irish setters, the dogs were bred very carefully to avoid conjoining two carriers. Last year when the Irish Setter Club of America did a health survey, they found no blind setters. Patterson feels that the diagnosis and control of genetic diseases will become an increasingly important part of veterinary practice. Presently, most vets have little knowledge of genetic diseases. But, later this year, Patterson's database will be published as a CD-ROM with a companion book outlining their diagnosis and control.
Most tests only identify a specific gene defect in a particular breed.
So although a disease may plague many breeds, the affected gene must be isolated and a test created for each of them. For example, Gustavo Aguirre, professor of opthamology at Cornell's Baker Institute, found that PRA, which afflicts not only Irish setters, but Labrador retrievers, poodles, American and English cocker spaniels and others, may be caused by a mutation to any one of at least seven different genes. Of the diseases where the gene is known, Giger predicts that the DNA defect will be known within the next decade. But a few years later, the disorder was identified in the Welsh corgi breed within months. Up until now, benefits from studies on the genetics of disease have flowed mainly from human to dog because of the mammoth research efforts in human genetics.