Juvenile Laryngeal Paralysis & Polyneuropathy (JLPP) in Black Russian Terriers
Researchers at the University of Missouri, College of Veterinary Medicine, working with collaborators around the world, have found the mutation associated with JLPP in Black Russian Terriers. A DNA test is now available to determine if a dog is a carrier of the mutation or at risk for JLPP. In researching this disease, we discovered that there was more to this disease than JLPP. In addition to those signs, affected dogs also have ocular abnormalities such as cataracts and they have a degenerative change in their brains with neuronal vacuolation. Thus you may also see this syndrome referred to as Polyneuropathy with Ocular Abnormalities and Neuronal Vacuolation (POANV).
If you suspect your dog has JLPP, see your veterinarian. As discussed below, there are many conditions besides JLPP that can cause these symptoms. Your veterinarian will be able to examine your dog to determine if one of these more common, potentially treatable diseases is causing your pet’s difficulties. If necessary, they can refer you to a Veterinary Neurologist board certified by the ACVIM. who can help them make the diagnosis. The DNA test can be ordered through the Orthopedic Foundation for Animals website (www.offa.org). To order a test,
What is Juvenile Laryngeal Paralysis & Polyneuropathy?
The brain controls muscles via signals that travel through nerves. A disease that affects the nerves is called a polyneuropathy: poly- (many), neuro- (nerves), -pathy (a disease). Due to a quirk in the way an embryo develops, one of the longest nerves in the body supplies the muscles of the voice box (larynx). The vocal folds vibrate as air moves over them allowing a dog to bark. When the dog breathes in, muscles in the larynx pull the vocal folds aside so that air can move easily into their lungs. These nerves also help to close the larynx when the dog swallows so they do not choke on their food.
If nerves are unable to convey messages properly, the muscles become weak or paralyzed. The longest nerves are often affected first; hence laryngeal paralysis is the first symptom. The vocal folds cannot be pulled out of the way as the dog breaths in. They vibrate noisily and can obstruct the flow of air into the lungs particularly when the dog is exercised or hot. The dog may also choke on their food or water or regurgitate, which can result in pneumonia.
The next longest nerves in the body go to the back legs, thus they are affected next. The dogs have difficulty getting up and wobble as they walk. Eventually the front legs will also be affected. The symptoms do not occur until after weaning age, and thus the disease is called juvenile laryngeal paralysis/polyneuropathy or JLPP for short.
What does JLPP look like?
If your dog shows signs of JLPP, see your veterinarian. They will be able to utlize the results of the DNA test and their findings on examination to determine if your dog is suffering from JLPP and advise you appropriately.
In addition to difficulty breathing and using the rear limbs, dogs with JLPP may have difficulty swallowing and may inhale food. This can result in serious pneumonia. As the disease progresses, dogs with JLPP can become unable to walk at all.
What else can look like JLPP?
There are other, much more common diseases that can affect a pup’s ability to breath. The windpipe (trachea) is stiff to keep it open when the dog is breathing hard. In some dogs, particularly toy breeds, the trachea does not have the proper stiffness and it can collapse as the dog breathes producing a honking cough. This condition is called collapsing trachea. An infection of the trachea such as kennel cough can cause irritation to the trachea and a similar sounding cough. The major difference is that dogs with tracheal disease cough when breathing out, while laryngeal paralysis produces noise when the dog breathes in. Infections can cause swelling of the tonsils & lymph nodes around the throat in a young pup (strangles) shich can make it difficutl for the pup to breathe. Finally, other diseases of the nervous system, such as distemper infections, can affect nerves producing signs of weakness, sometimes with pneumonia. Laryngeal paralysis also occurs in older dogs, but JLPP is different because they develop paralysis at such a young age.