Researchers have discovered linkages between the skin condition known as atopic dermatitis (eczema) in dogs and many parts of the genome by utilizing new methods for mapping genes. Some of the genes that were found are the same as genes that have been associated to comparable disorders in humans. The area of the filaggrin gene, for example, which is recognized as the most significant risk factor for atopic eczema in humans, has now also been related to this condition in Labrador retrievers. This disease is associated with severe itching and inflammation of the skin.
The results are reported in a new study that was produced by the dog genetics group at Uppsala University and the Swedish University of Agricultural Sciences. This team has been conducting studies in this area for more than ten years in partnership with colleagues from Switzerland, the United Kingdom, and the United States.
At the beginning of the 2000s, sequencing of whole genomes became achievable. Since then, researchers who are interested in understanding the human genome have found that sequencing the dog genome is quite helpful.
Dogs and humans have coexisted for tens of thousands of years, and both species are susceptible to a number of the same illnesses, including immunological conditions like atopic dermatitis (allergic eczema). Researching the genetics of canine diseases with regular blood samples can also be a means to get information on the factors that contribute to the development of the corresponding human diseases.
Dogs and people that suffer from atopic eczema have many of the same medical symptoms, as well as an early beginning of the condition, and in terms of histopathology, both suffer from comparable immune cell infiltration in the skin. The genetic history of the illness is complicated in both species, and environmental variables are also a contributing element in its development.
It’s vital that atopic eczema is properly diagnosed by carefully eliminating other possible non-allergic causes of the patient’s symptoms, followed by a positive allergy test, according to Kerstin Bergvall, the veterinarian in charge and specialist in dermatology who has been involved in the study from the very beginning.
In recent years, new approaches to mapping complicated disorders have surfaced as a direct result of the continuous technological advancements for mapping genes. In the study that has just been published in the journal Communications Biology, the researchers used one method to capture multiple associated genetic risk variants and also another approach to discover disease variations that were “invisible” in the genome due to unnaturally (or humanly) selected characteristics. Both methods were used in the same study.
Katarina Tengvall, a researcher at Uppsala University and the first author of the study, explains that the new approaches make it possible to find new risk factors that are now common in the specific breed, possibly as a result of the selection for other characteristics. As predicted in individuals with atopic eczema, the candidate genes that were found here play a crucial role in both the composition of the skin barrier and the immunological response.
The research reveals a number of identical patterns, also known as correspondences, with genes connected to human atopic dermatitis. The fact that the genomic area that contains the filaggrin gene, which is considered to be the most potent genetic risk factor for atopic eczema in humans, is also a risk factor in dogs. The finding was a startling discovery for the researchers.
This demonstrates how important it is to conduct research on canine models of genetic illnesses that also impact people. A more complete knowledge of the mechanisms underlying the disease may, in the long run, result in the development of more effective treatments for both dogs and humans according to Professor Kerstin Lindblad-Toh, who was also the study’s senior author and specializes in comparative genomics.
Sources:
Katarina Tengvall et al. (2022). Bayesian model and selection signature analyses reveal risk factors for canine atopic dermatitis, Communications Biology. DOI: 10.1038/s42003-022-04279-8
https://phys.org/news/2022-12-atopic-dermatitis-dogs-linked-genome.html
