Tag Archives: PLoS Genetics

Cleft palate in dogs

UC Davis School of Veterinary Medicine researchers have identified the genetic mutation responsible for a form of cleft palate in the dog breed Nova Scotia Duck Tolling Retrievers.

Photo by Danika Bannasch/UC Davis

Photo by Danika Bannasch/UC Davis

They hope that the discovery, which provides the first dog model for the craniofacial defect, will lead to a better understanding of cleft palate in humans. Although cleft palate is one of the most common birth defects in children, affecting approximately one in 1,500 live human births in the United States, it is not completely understood.

By conducting a genome-wide study of this breed with a naturally occurring cleft palate, researchers identified a mutation responsible for the development of cleft palate. Dogs with this mutation also have a shortened lower jaw, similar to humans who have Pierre Robin Sequence. The disorder, a subset of cleft palate, affects one in 8,500 live human births and is characterized by a cleft palate, shortened lower jaw and displacement of the tongue base.

Cleft palate condition occurs when there is a failure in the formation of the secondary palate, which makes up all of the soft palate and the majority of the hard palate.

The team have published their study in the journal PLOS Genetics.

Source:  UC Davis media release

Researchers identify gene associated with eczema in dogs

A novel gene associated with canine atopic dermatitis has been identified by a team of researchers led by professors Kerstin Lindblad-Toh, Uppsala University and Åke Hedhammar, SLU, Sweden. The gene encodes a protein called plakophilin 2, which is crucial for the formation and proper functioning of the skin structure, suggesting an aberrant skin barrier as a potential risk factor for atopic dermatitis.

Details appear in the open-access journal PLoS Genetics.

Atopic dermatitis (or eczema) is an inflammatory, relapsing non-contagious skin disease affecting about 3-10 percent of dogs. The skin of a patient with atopic dermatitis becomes easily irritated by various allergens such as certain types of food, pollens or house mites. Such irritation causes very strong itching which leads to scratching, redness and flaky skin that becomes vulnerable to bacterial and yeast infections.

Despite many scientific efforts, little has been known about the genetics of the disease. In their study, researchers from Uppsala University, SLU and Broad Institute, compared DNA samples from a large group of German shepherd dogs affected by atopic dermatitis with DNA coming from healthy dogs to reveal the specific DNA segment associated with the disease.

“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 first author Katarina Tengvall, Uppsala University.

Purebred dogs such as German shepherds have been selected for specific physical features for several generations. Selection led to an inadvertent enrichment for disease-risk genes in certain breeds. Moreover, the resulting architecture of canine DNA makes it easier to pinpoint segments that carry these disease risk-genes. This helped the researchers to reveal the genetics of atopic dermatitis. They found a region associated with the atopic dermatitis containing the gene PKP-2, which encodes Plakophilin-2, a protein involved in the formation and maintaining of the proper skin structure.

“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,” continues Katarina Tengvall.

These findings will not only lead to better understanding of the disease, which may lead to better treatment strategies long term. It also opens up the possibilities of development of a genetic test for the disease.

“Our study suggests that plakophilin-2 and an intact skin barrier is important to avoid atopic dermatitis”, says senior author, Kerstin Lindblad-Toh, professor at Uppsala University and Director of SciLifeLab Uppsala. “Another gene involved in the skin barrier has recently been linked to human atopic dermatitis emphasizing the similarity between canine and human atopic dermatitis” said Kerstin Lindblad-Toh.

Source:  AlphaGalileo Foundation media statement