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GSD ATOPIC DERMATITIS GENE IS NO PANACEA
By Susan Chaney
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.
Although isolation of some genes related to atopic dermatitis in German Shepherd Dogs is
helpful, it’s not a solution..
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.”