Swedish researchers have identified a gene linked to eczema in dogs, which helps explain why certain purebred breeds, like German shepherds, are more likely to develop the skin condition.

Eczema, also known as atopic dermatitis, is a non-contagious skin disease that is estimated to affect at least one out of 10 of all humans. The inflammatory skin condition can be triggered by common allergens like certain foods or pollen, causing itchy, flaky, and red rashes that leave people vulnerable to infection.

The condition often runs in families, but the genetics of eczema are incompletely understood.

Previous research has implicated an abnormal mutation in a gene encoding the protein filaggrin, which helps moisturize skin and keep it intact, though many people without that mutation still develop eczema. Other recent studies identified abnormal genes linked to the immune system and inflammatory response.

The new study, published today in the journal PLoS Genetics, identifies abnormal functioning in a gene called PKP2 that encodes the plakophilin-2 protein, which promotes and maintains a healthy skin barrier.

Scientists at Uppsala University in Sweden examined the genetics of canine eczema, since 3 to 10 percent of dogs suffer from the skin condition.

"With the help of pet owners, we have managed to collect a unique set of DNA samples from sick and healthy dogs which allowed us to gain insight into atopic dermatitis genetics," said study author Katarina Tengvall in a news release.

They focused on purebred German shepherds, which are a breed with particularly high risk for eczema, collecting DNA from 207 pet dogs with and without it.

Genetic analysis revealed that German shepherds with certain mutations in the PKP2 gene had a much higher risk of eczema, suggesting that low levels of the plakophilin-2 protein break down the skin barrier in dogs with the mutation.

"The finding that certain variants of the PKP-2 gene may increase the risk of developing the disease opens new possibilities in understanding the disease mechanism leading to atopic dermatitis," said Tengvall in her statement.

That raises the possibility of a genetic test for eczema, especially if, as senior author Kerstin Lindblad-Toh suggested in the news release, similar gene mutations are responsible for atopic dermatitis in both dogs and humans.

Eventually, treatments may directly compensate for deficient genes that lead to the skin condition.

The full study is available for free at PLOS Genetics.