Tay-Sachs disease has been discovered in a rare breed of sheep known as Jacob sheep. Their discovery is due to the persistence of Fred and Joan Horak, Texas farmers who noticed, in 1999, among their flock of Jacob sheep, two lambs that had developed signs of a nervous system disorder while still very young. Veterinary studies convinced them that the sheep had a lipid storage disease, but no
enzyme deficiency could be found.
Fred and Joan realized that they had encountered an inherited disease and because they kept good records on their flock, they knew the parental origin of the affected sheep. They could have removed these animals from their breeding stock, but instead kept the
gene around so that perhaps someday it would be better understood.
It took more than a decade to solve the mystery. Dr. Brian Porter, a veterinary pathologist at Texas A&M, referred the Horaks to Dr. Edwin Kolodny at New York University Medical Center, a member of the Tay-Sachs Gene Therapy (TSGT) Consortium. Dr. Kolodny’s lab began putting the pieces of the puzzle together and discovered that the Jacob sheep had Tay-Sachs disease.
Fred and Joan Horak were elated that a cause had finally been found to explain why their lambs had died, and the TSGT Consortium quickly realized the potential of Jacob sheep as a large animal model for gene therapy trials. The Horaks agreed to enlarge their flock in favor of carriers in the hope that a few affected lambs could be produced. In the breeding 2009 season, four lambs were born with Tay-Sachs disease. By three months of age, three of these lambs were already showing neurological signs.
The Horaks then donated the affected animals and others from the flock to NTSAD and the veterinary school at Auburn University where Dr. Douglas Martin and Dr. Miguel Sena-Esteves quickly mobilized to start gene therapy experiments in these sheep. The initial results have been promising, although more animals will be needed to perform further gene therapy studies. Fred and Joan are prepared to do their part. To recognize all that they have done to help advance research, the Horaks received the Above and Beyond Award at the 2010 NTSAD Annual Family Conference.
Financial support is needed to perform these gene therapy studies in a larger number of Tay-Sachs sheep and help maintain the sheep flock. If you would like to help fund the research and maintain the sheep flock by naming a sheep for $1,000 or participate in the Adopt-A-Sheep program, please contact the office.
The research report for year 1 of the sheep study is available in our Library.
