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.

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.