Ligneous Membranitis

Ligneous Membranitis is a rare inflammatory disease of the mucous membranes. The disease causes conjunctivitis, mouth ulcers and swollen gums. Other clinical signs include nasal discharge, loud breathing and enlarged lymph nodes.

Key Signs

Ulcerative conjunctivitis, Ulcerative stomatitis, Ulcerative gingivitis

Age of Onset

0 to 2 yrs

Juvenile onset


Autosomal Recessive

For autosomal recessive disorders, dogs with two copies of the variant are at risk of developing the condition. Dogs with one copy of the variant are considered carriers and are usually not at risk of developing the disorder. However, carriers of some complex variants grouped in this category may be associated with a low risk of developing the disorder. Individuals with one or two copies may pass the disorder-associated variant to their puppies if bred.

Likelihood of the Condition

High likelihood

At risk dogs are highly likely to show signs of this disease in their lifetime.

What to Do

Here’s how to care for a dog with Ligneous Membranitis

Partner with your veterinarian to make a plan regarding your dog’s well-being, including any insights provided through genetic testing. If your pet is at risk or is showing signs of this disorder, then the first step is to speak with your veterinarian.

For Veterinarians

Here’s what a vet needs to know about Ligneous Membranitis

Clinical signs of ligneous membranitis include progressive oral and ocular inflammatory lesions which occur within the first few weeks to months of life. Affected dogs may have ulcerative inflammation in the mouth and the conjunctiva of the eyes. Other clinical signs include nasal discharge, loud respiratory sounds, and enlarged lymph nodes. Blood work may show neutrophilia, proteinuria, and hypoalbuminemia as well as low plasminogen activity. Affected dogs may have inflammatory fibrinous changes in the trachea, larynx, and in the thoracic and abdominal cavities.

The prognosis for affected dogs with this condition is poor. Euthanasia is often elected for surviving puppies due to welfare concerns.

For Breeders

Planning to breed a dog with this genetic variant?

There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.

This disease is autosomal recessive meaning that two copies of the mutation are needed for disease signs to occur. A carrier dog with one copy of the Ligneous Membranitis mutation can be safely bred with a clear dog with no copies of the Ligneous Membranitis mutation. About half of the puppies will have one copy (carriers) and half will have no copies of the Ligneous Membranitis mutation. Puppies in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier matings are not advised as the resulting litter may contain affected puppies. Please note: It is possible that disease signs similar to the ones caused by the Ligneous Membranitis mutation could develop due to a different genetic or clinical cause.

Technical Details

Gene PLG
Variant T>A
Chromosome 1
Coordinate 49,514,382

All coordinates reference CanFam3.1

References & Credit

Credit to our scientific colleagues:

Ainsworth, S., Carter, S., Fisher, C., Dawson, J., Makrides, L., Nuttall, T., & Mason, S. L. (2015). Ligneous membranitis in Scottish Terriers is associated with a single nucleotide polymorphism in the plasminogen (PLG) gene. Animal Genetics, 46(6), 707–710. View the article