Common Symptoms
Ligneous membranitis is an inherited, chronic inflammatory disease affecting dogs. Affected dogs present by two months of age with severe ulcerations of mucous membranes including those of the mouth, eyes, and respiratory tract resulting in pain and discharge from the eyes and nose. Affected dogs will often display increased respiratory sounds due to severe inflammation of the larynx and trachea. Enlarged lymph nodes, increased white blood cell counts, protein in the urine, and inadequate amounts of protein in the blood are commonly seen with this disease. Additionally, affected dogs often have severe, chronic inflammatory changes of the membranes lining the chest and abdominal cavities. Some affected dogs may be born with malformation of the Cerebellum, a part of the brain associated with coordinated movement. Affected dogs typically die or are euthanized before adulthood due to the severity of the disease and quality of life concerns.
Testing Tips
Genetic testing of the PLG gene will reliably determine whether a dog is a genetic Carrier of ligneous membranitis. Ligneous membranitis is inherited in an Autosomal Recessive manner in dogs meaning that they must receive two copies of the mutated gene (one from each parent) to develop the disease. In general, carrier dogs do not have features of the disease but when bred with another carrier of the same Mutation, there is a risk of having affected pups. Each pup that is born to this pairing has a 25% chance of inheriting the disease and a 50% chance of inheriting one copy and being a carrier of the PLG gene mutation. Reliable genetic testing is important for determining breeding practices. In order to eliminate this mutation from breeding lines and to avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Dogs that are not carriers of the mutation have no increased risk of having affected pups.
There may be other causes of this condition in dogs and a normal result does not exclude a different mutation in this gene or any other gene that may result in a similar genetic disease or trait.
References
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Ainsworth S, Carter S, Fisher C, Dawson J, Makrides L, Nuttall T, Mason SL. Ligneous membranitis in Scottish Terriers is associated with a single nucleotide polymorphism in the plasminogen (PLG) gene. Anim Genet. 2015 Dec;46(6):707-10. doi: 10.1111/age.12339.
[PubMed: 26360520]
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Mason SL, Fisher C, Ressel L, Bommer NX, Buckley LM, and Nuttall T. Presentation, clinical pathological and post-mortem findings in three related Scottish terriers with ligneous membranitis. J Small Anim Pract. 2016 May;57(5):271-276. doi: 10.1111/jsap.12443.
[PubMed: 26840763]
