One day not too long ago, my mom came home with this little box containing two cotton swabs. They looked like they had something to do with genetic testing. When she called me over with them in her hand, I began to get a little concerned. She was about to do something so me and I wasn’t sure I was going to be too happy about it.
But I went to her like I knew I should. She helped me open my mouth, stuck one of those swabs in my mouth. They were scratchy. She twirled one inside my cheek and then took the other swab and did the same thing to the other cheek. I just looked at her questioningly.
“We’re getting DNA for testing,” she explained. Well, I’m a dog and I don’t know what all that means. But if it was important to her, I knew it must be important for me. So I didn’t complain. She packed up the swabs in a box and put them in the mail. Then we waited.
What I learned later was that my mom wanted me tested for VDEGS. That means Van den ende-Gupta Syndrome, It’s something that can happen to wire fox terriers if their genes aren’t right. It can happen to people too.
A Terrible Genetic Disorder
According to Animallabs.com, VDEGS is a genetic disorder that affects wire fox terriers. Dogs that have it have a prominent underbite and a short maxilla. That’s the upper jaw bone. The caudodorsal border of the maxilla is slightly convex. That means the border near the back of the upper jaw bone. Puppies have elbow luxation (bone separated from the joint) on both sides and secondary ossification centers occur. Ossification is the natural process of bone formation. Secondary ossification is bone formation that happens after the initial formation.
The mid-thoracic spine is thinner, longer and more horizontally aligned. In affected dogs, the mid-section of the femoral bones bow. Their eyes look smaller and the sclera (white of the eye) is thinner. Because of maxillary hypoplasia (underdevelopment), the nose is distinctive. Bones of the feet are slender. Knee joints often are swollen and patellar (knee cap) luxation is present. Nasal septum is deviated to the left.
VDEGS is caused by a mutation of the SCARF2 gene in wire fox terriers and in humans. The SCARF2 gene is the scavenger receptor class F member 2 gene. That means they are genes that give instructions to protein to do whatever they are supposed to do in your body. The result is that some genes are shorter than they are supposed to be.
Now, we’re getting a little too complicated here and, if I’m not careful, not only will you now know what I’m talking about. Neither will I.
VDEGS is inherited in an autosomal recessive pattern in dogs. For a puppy to be affected (have VDEGS) both parents have to be carriers of the mutated SCARF2 gene. But, if two carriers are mated, it isn’t a guarantee that all the puppies in the litter will have VDEGS. Each puppy will have a 25 percent chance of having VDEGS. Each will have a 50 percent chance of being an unaffected carrier and each will have a 25 percent chance of being neither affected or a carrier. In the latter case, they would be considered clear.
If a carrier and a clear dog are bred to each other, worst case scenario is that some of the puppies could be carriers and some could be clear. You just have to see how the genes shake out in the end. If both parents are clear, then so are the offspring.
In order to find out “how the genes shake out,” DNA testing is necessary. That’s what my mom was doing to me.
Now, the interesting thing is that people can get VDEGS too. But it rarely happens, thank goodness. Babies with VDEGS also have maxillary hyperplasia, a beaked-looking nose, underdeveloped eyelids, bent fingers and a cleft palate, among other things.
We’re not going to get into the history of dogs as a species here, but we do need to mention that most of the breeds of purebred dogs are no more than 200 years old. That isn’t very long when compared to how long the human species has been evolving.
What we see in dogs today is largely a result of selection driven by dog breeders who like certain features of their breed. Registering bodies like AKC and the breeding standards they have published, has led to controlled and restricted breeding practices. Many breeds have come from a limited number of founder animals and the use of popular sires is common. This has resulted in each breed representing an isolated breeding population with reduced genetic diversity and enrichment of breed-specific disorders.
How Dogs Help Scientists Study Human Genetic Disorders
The canine genome has been sequenced just like the human one and scientists have found it to be less divergent from the human genome that the mouse genome, which often is used in studies. This is where we wire fox terriers have become heroes. Move over mice and let the real superheroes take their rightful place on the stage.
Because it is less divergent, more of the human genomic sequence can be aligned to the genome of the dog than that of the mouse. Dogs have approximately the same number of genes as humans, most of them being close despite the fact they are from different species.
Furthermore, dogs are a large animal model and physiologically and clinically more similar to human than the mouse. Pet dogs share the environmental conditions of their owners and are not only affected by genetic traits but also by “life style.” Many spontaneously occurring common canine conditions are like human diseases such as diabetes, cancers, epilepsies, eye diseases and autoimmune diseases.
A lot of genealogical data also is available for us dogs. You know all those pedigrees you people keep. That’s what I’m talking about. These can help in designing genetic studies. There is a giant bank of information on more than 300 breeds in Finland. Using all this information and the other tools available to scientists, they have made several new gene discoveries in dogs and some of these include developmental disorders that model human pediatric disorders.
One is VDEGS. At the time this research was done, only 30 children with VEDGS had been identified. But that’s 30 too many.
Human and canine VDEGS patients share many characteristics, as we’ve already listed. Therefore when SCARF2 was discovered and established a canine diagnosis, it also established a model for human VDEGS. The mouse model didn’t work and there were, thankfully, too few humans for study, this discovery was a major breakthrough. Additionally, some VDEGS dogs live to be 10 or more years old. This means they could serve as preclinical models for further study.
There’s a lot still to be learned about this horrible VDEGS thing, but thanks to us wire fox terriers, we’ve got a good start.
Genetic Testing for Dogs
So now, back to my cheek swabbing.
My mom sent the test off to something called Wisdom Panel and they sent her back a report. All my canine family got theirs done too. We learned that I am a carrier. My half brother and two of my nieces are clear. My best friend (and cousin) has one daughter that is clear and one that is a carrier.
What this means to us is that our mom has to be careful. She had to do her research when she is preparing to do a breeding. I’m not going to be breeding with anyone, because I kind of like the bachelor life even though I do have a best friend who is a girl.
But, if one of our carrier girls is going to get bred, my mom has to be sure the father she chooses is clear. Doing otherwise would be irresponsible. And that is one thing a breeder should never be.
If you want to get your dog tested, check Wisdom Panel’s website at wisdompanel.com. The test will tell you about more than 200 different genetic thing, even what breed your dog is if you don’t already know.
And don’t forget, if you like to read and you like wire fox terriers, run over to Kindle and grab Murder at Ring 5 – A Mathias Dog Show Mystery. If you have Kindle Unlimited, you can borrow it for free. If not, it will cost you only $2.99.