"Saint Bernard dogs may suffer from neuromuscular diseases collectively termed Laryngeal Paralysis and Polyneuropathy. Affected dogs may have noisy breathing, a change in their bark, and difficulty breathing due to involvement of the larynx and laryngeal folds in the throat. Additionally, they may suffer from slowly worsening exercise intolerance and develop gait abnormalities, such as an exaggerated hitched step, especially in the hind limbs. There is often wasting of the hind limb muscles as well. Eventually the disease may progress to the point where the dog cannot support its own weight and surgical intervention for laryngeal paralysis may be required. Biopsies of nerve from affected dogs show degradation of the nerve fibers and loss of myelin, the insulating material that normally helps speed messages along nerves. Muscle biopsies show atrophy resulting from nerve loss. Research carried out at the University of Minnesota, the University of Bern, and the University of California, San Diego - Comparative Neuromuscular Laboratory indicates that laryngeal paralysis and polyneuropathy within the Saint Bernard breed is a group of several genetically distinct, but clinically similar diseases. We have mapped one major genetic risk loci (originally identified in Leonberger dogs) and identified the causative mutation that we now term Leonberger Polyneuropathy type 1 (LPN1)." [From University of MN]