French bulldogs can have breathing problemsMichelle Guillermin/EyeEm/Getty By Donna LuMany English and French bulldogs develop breathing difficulties, and the flat faces of these breeds have long been thought to be responsible, but now a gene mutation in these dogs suggests that face shape isn’t the only culprit. Jeffrey Schoenebeck at the University of Edinburgh, UK, and his colleagues have found a mutation in a gene called ADAMTS3, which is also present in Norwich terriers. Norwich terriers often suffer from similar breathing problems even though they have proportional noses. Advertisement