Some dog breeds may have trouble breathing because of a mutated gene

Norwich terriers don’t have flat snouts, but can suffer the same wheezing as bulldogs

Norwich terrier

DOG BREATH  Some Norwich terriers’ breathing troubles might rest on a mutated gene linked to swelling around airways, researchers suggest. The gene may also contribute to the labored breathing of dogs with flatter snouts, such as French and English bulldogs.  

Marcia A. Sessions

Dogs with flat faces aren’t alone in their struggle to breathe. It turns out that Norwich terriers can develop the same wheezing — caused not by the shape of their snouts, but possibly by a wayward gene. 

DNA from 401 Norwich terriers revealed that those suffering a respiratory tract disorder shared the same variant of gene ADAMTS3 that’s associated with swelling around airways. Nearly a third of the dogs had two copies of that mutated gene. And those same dogs scored worse on airway-function tests than dogs with just one copy or the normal versions of the gene, researchers report online May 16 in PLOS Genetics.

The gene variant, which does not hinder the gene’s main function in the development of lymphatic vessels, also turned up in the DNA of French and English bulldogs. That finding indicates that those pooches’ smooshed snouts might not be the only factor behind their labored breaths.

“This is the first evidence to show that it’s not just all about skull shape,” says study coauthor Jeffrey Schoenebeck, an animal geneticist at the University of Edinburgh’s Roslin Institute.

The research might someday help dog breeders build healthier pups. Schoenebeck suggests that a genetic test could be developed to identify Norwich terriers with the genetic variant. Breeders could then use the test to keep those dogs from reproducing and passing the mutation along.

Cassie Martin is a deputy managing editor. She has a bachelor's degree in molecular genetics from Michigan State University and a master's degree in science journalism from Boston University.

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