An Interview on the subject of SCID in Arabian Horse
In 1988, a team of Ph.D. molecular geneticists from Michigan State University School of Veterinary Medicine and from University of Michigan Department of Human Genetics came together to study canine genetic diseases. Team members quickly verified the existence of such conditions and developed a research strategy to deal with them. Briefly, out of the research, the MSU/UM team developed several tests to detect various genetic defects. In 1995, the group became VetGen LLC and moved from the university environment into the commercial marketplace. Since then, VetGen has launched a variety of genetic disease detection services and is now considered the leader in veterinary genetic disease research and genetic disease detection services for purebred animals. In 1997 VetGen was selected by the University of Texas Southwestern Medical Center as the exclusive facility to offer the SCID test.
Here's an interview with John Duffendack, President and CEO of VetGen.
Please walk us through a typical SCID test at VetGen.
The owner or veterinarian obtains a blood sample or a cheek swab of the horse to be tested, completes the proper paperwork, and sends them off to us. The test takes about two weeks to run. Results of the test are read independently by two different people. Results are not interpreted. There's no judgment involved. The test gives a definite answer: yea or nay. There are no false positives or false negatives.
How can owners be assured of the confidentiality of the testing process?
The results are confidential, period. We take the proper precautions and use lab procedures to ensure confidentiality. (If we were to explain them, people could figure out how to get around them.)
Please explain the benefits of testing suckling foals.
Testing has proven helpful when a foal becomes ill. Unless both parents have tested clear, a veterinarian treating a foal with pneumonia or an opportunistic infection wants to know whether or not the foal is a SCID foal. The treatment for infections is expensive and aggressive and difficult for the foal and heartbreaking for the owner. If the foal is going to die no matter what, no one wants to put an animal through that kind of torture. We've done a number of tests on foals, both from the United States and from overseas.
In about eight months of testing, what has VetGen learned about frequency of occurrence of SCID foals?
When the number of tests is large enough - a year or more from now - we can make some statements about generalized disease frequency and if there is a sufficient demand by organizations representing breeders as a whole, we might release some broad-base statistics. What we've done so far certainly shows that the carrier frequency is well within what researchers have reported in the past. But our figures may be biased because of the newness of the test, and we're not sure which way. Are we testing more suspect animals, or are owners rushing to establish a clear status on their horses?
Will VetGen do research to associate the carrier status with other qualities of the breed such as particularly desirable traits? Or with color?
You are talking about very expensive research. We can't say that it is or it isn't.
Please explain the price structure for SCID testing.
- One horse $180
- Two to six horses (owned by one person) $150 each
- Seven to 15 horses (owned by one person) $125 each
- Sixteen or more horses (owned by one person) $99 each
- Sample collection kits (for blood or cheek swabs) $5 each
The SCID testing is not yet profitable for VetGen; we're hoping someday it might be. Our PCR (polymerase chain reaction) royalty alone on this test is about $14 or $15, plus other royalties (the universities, the researchers), so we're probably paying $25 to $30 in royalties and fees right off the top. Professional liability insurance, salaries for those conducting a labor-intensive test, and the cost of sophisticated lab equipment add to our expenses. Plus we have to maintain an approved radiation laboratory and to satisfy various federal, state, and local regulations. It's not just running a ma-and-pa filling station. Long-term, we hope the costs will come down as technology advances and the volume goes up, but probably not in the next few years.
To what extent do you do "genetic counseling" with your clients?
In reporting test results to owners, each horse is categorized as clear, carrier, or affected. Clients are furnished with these expansions of the categories along with a breeding strategy summary:
- Clear. This finding indicates that the gene is not present in the horse. When used for breeding, a clear animal will not pass on the disease gene.
- Carrier. This finding indicates that one copy of the disease gene is present in the horse, but that it will not exhibit disease symptoms. Carriers will not have medical problems as a result. Horses with carrier status can be enjoyed without the fear of developing SCID, but they will pass on the disease gene about 50 percent of the time.
- Affected. This finding indicates that two copies of the disease gene are present in the horse. Unfortunately, the horse will be medically affected by the disease; all SCID-affected foals die within several months of birth. Appropriate treatment should be pursued by consulting a veterinarian.
A section of the report entitled "Breeding Strategies" provides information on expected outcomes of clear-to-clear matings, of clear-to-carrier matings, and of carrier-to-carrier matings.
Your feelings about the impact of the SCID test?
The real value of this test is that breeders can use it to ensure that they will never produce a SCID foal, and that they can, by breeding carriers to clears, preserve the unique and positive characteristics of exceptional carriers. And thereby breed out the undesirable gene over several generations. So we think of the test in a very positive way in that it allows people to no longer fear carriers and to no longer fear SCID.
For further information or to order test kits, contact VetGen at:
3728 Plaza Drive, Suite 1, Ann Arbor, Michigan 48108.
Phone US and Canada only 1-800-4VETGEN (800-483-8436)
Fax (734) 669-8441.
Our online contact page