We are currently undertaking a study at the University of Liverpool, investigating the genetics of ligneous membranitis in a family of Scottish terriers. This is a rare chronic inflammatory disease of the mucous membranes associated with plasminogen deficiency. The condition is well characterised in humans and is inherited in an autosomal recessive pattern (Schuster and others 2001, Tefs and others 2006, El-Darouti and others 2009, Gunhan and others 2012).
We have recently treated four related Scottish terrier puppies with ligneous conjunctivitis, all of whom died or were euthanased because of their disease. The affected animals presented with severe proliferative conjunctivitis (Fig 1), gingivitis and tracheitis, and some had proteinuria, bilateral muco-purulent nasal discharge and lymphadenopathy. Post-mortem examination revealed fibrinous lesions in the epicardium, mitral myxomatous degenerative valvular disease, and hydrocephalus. There were also multiple developmental abnormalities. The affected dogs presented initially at around 8 to 12 weeks of age.
There are only three previous reports of this condition in dogs, all in unrelated animals (Ramsey and others 1996, McLean and others 2008, Torres and others 2009), and to date no genetic studies in dogs have been performed. We plan to perform genetic studies to identify the mutation responsible for ligneous conjunctivitis in dogs.
We would be interested to hear from colleagues who have seen similarly affected Scottish terriers. We are collecting DNA from affected dogs and their relatives using buccal swab and plasma for plasminogen analysis.
We hope that by identifying the genetic mutation for this condition in dogs we can assess the prevalence of the disease in the canine population and provide breeders with appropriate advice on breeding future progeny.