Ligneous Membranitis
Affected Genes: PLG
Inheritance: Autosomal Recessive
Variant(canFam6):
chr1:50357385: A>T
Breed: Scottish Terrier
General Information: Ligneous Membranitis (LM) is a chronic, progressive inflammatory disease that typically begins manifesting in dogs by two months of age. This condition is characterized by persistent and severe ulcerations on the mucous membranes, particularly affecting the eyes, mouth, and respiratory tract, leading to painful sores and significant discharge. Dogs with this disease often experience difficulty breathing due to inflammation in the larynx and trachea, accompanied by respiratory noises. Systemic signs include enlarged lymph nodes, elevated white blood cell counts, proteinuria (protein in the urine), and hypoproteinemia (low blood protein levels). Severely affected dogs may also show malformations of the cerebellum, impacting their motor skills and coordination. Due to the debilitating nature and progressive worsening of symptoms, affected dogs rarely survive to adulthood, often necessitating humane euthanasia for quality of life reasons.
How to Read Your Dog's Test Results for this Genetic Variant:
Two Variants Detected: Dog Likely Affected
One Variant Detected: Dog Unlikely Affected
No Variants Detected: No Effect
Gene / Testing Information: Genetic testing for Ligneous Membranitis (LM) involves analyzing the PLG gene to identify carriers of the condition. This disease is autosomal recessive, meaning a dog must inherit two copies of the mutated gene—one from each parent—to exhibit the disease. Carrier dogs, possessing only one copy of the mutation, typically do not show any clinical signs but can pass the mutation to their offspring. When two carriers are mated, each puppy has a 25% chance of being affected by the disease, a 50% chance of being a carrier, and a 25% chance of being completely clear. For responsible breeding practices, it is crucial to test breeding dogs to prevent the unintentional breeding of carriers, which would increase the risk of producing affected pups. Breeding strategies should aim to avoid mating carriers together to prevent the birth of affected puppies and reduce the prevalence of this debilitating disease in future generations.
References:
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 46(6):707-710.
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 57(5):271-276.