Ligneous membranitis (LM) is a rare chronic inflammatory condition of the mucous membranes. (as of 2015) The condition is uncommonly reported in dogs. For the research into this test, the researchers identified the risky genes using Scottish Terriers. Symptoms include: severe conjunctivitis, gingivitis, and respiratory distress. Hypoplasminogenaemia was confirmed in one of the three affected dogs. Supportive treatment was not effective, and the dogs died or were euthanased because of the disease. Post-mortem analysis of two of the dogs revealed multiple abnormalities including severe proliferative fibrinous lesions affecting the conjunctiva, gingiva, trachea, larynx and epicardium and multiple fibrous adhesions throughout the thoracic and abdominal cavities. One dog had internal hydrocephalus and lacked a cerebellar vermis. Ligneous membranitis was confirmed on histopathology. This is a rare condition in dogs but an important differential diagnosis for severe conjunctivitis and gingivitis.