Last week’s headline, “Researchers identify gene associated with eczema in dogs,” on the AlphaGalileo Foundation website, got me excited. Having researched atopic dermatitis for an article last September, I immediately imagined what this could mean for dog owners everywhere.
However, as is often the case with headlines, the story revealed a less promising tale – not an un-promising tale, just less promising.
It is true that researchers at Uppsala University and the Swedish University of Agricultural Sciences, both in Uppsala, Sweden, have isolated a region of eight genes on chromosome 37 of the canine genome associated with the tough-to-combat skin condition. However, it is only in German Shepherd Dogs.
The genes partially responsible for a proclivity toward atopic dermatitis have been identified in other breeds as well, according to Patrick Hensel, Dr.med.vet., a diplomat of the American College of Veterinary Dermatology and an associate professor of dermatology at the University of Georgia College of Veterinary Medicine in the city of Athens.
You’d think that dog owners would be getting fewer diagnoses of atopic dermatitis after these discoveries.
But again, it’s not quite that simple.
Atopic dermatitis involves several body processes, Hensel explains, thus genetic material responsible for inflammation, cell death, skin barrier formation and others contribute to whether a particular dog will or won’t develop it. Most genetic studies have found “several genes” affecting a single process, he says.
In addition, the environment in which a dog lives “plays a major role too,” he says, “since you can have two dogs with the same genetic predisposition, but one will develop AD and the other not. This is one reason why it is not that easy to get rid of AD in a breed through breeding programs.”
The genetic area “detected in the German Shepherd is one which is affecting the skin barrier,” Hensel says. That skin barrier has become “an important target” for allergy research, he adds.
While it might be discouraging to hear that these genetic discoveries, followed by the development of tests for the particular genes in a particular breed, can’t, on their own, prevent atopic dermatitis, the news is not all bad. “The good thing about these genetic tests is that once we know which gene and process are involved, we may be better able to improve our allergy management.”
To isolate this genetic area, the researchers looked at GSDs with lowered Immunoglobulin A, known as “IgA,” an antibody that plays an important role in immunity. “Serum IgA levels are known to be lower in GSDs compared to other breeds. We detected significantly lower IgA levels in the [canine atopic dermatitis] cases compared to controls,” the researchers write in the abstract of their study results which were published on May 9 by the online journal PLOS Genetics.
The team concluded: “The PKP2 [plakophilin 2] gene found within the associated region” has become “an interesting target for further study of its importance both in canine and human AD.”