Genetics and characteristics
Ligneous membranitis (LM) is a chronic inflammatory condition of the mucous membrane caused by changes within the plasminogen gene. The inherited condition is well described in humans and it has also been reported in dogs, in the Scottish Terrier breed. Affected dogs show clinical signs that include increased upper respiratory tract noise, nasal discharge, and different ocular, oral and genital lesions that can progress over time and potentially lead to euthanasia. A single nucleotide change within the PLG gene results in a potential truncation of the protein affecting its functionality and causing its deficiency. Plasminogen has an important role in many physiological processes including embryogenesis, wound healing, breakdown of clots, cell migration, and formation of new blood vessels.
This type of chronic inflammatory condition that affects Scottish Terrier dogs is inherited as an autosomal recessive trait meaning two copies of the mutated gene are required for the disease to develop. That means Scottish Terrier dogs with only one copy of the mutated PLG gene will not develop the disease but can act as carriers of the mutation. Early genetic testing can help identify affected dogs that carry the mutation and prevent their further breeding by proper selection of mating pairs and the development of the disease in puppies.
Results Reported As
Test Result |
Interpretation of test result |
CLEAR |
Tested mutation was not detected in animal with „clear“ result. Animal tested as clear has wild-type allele in homozygous state (i.e. two pairs of healthy alleles). It will not develop disease caused by tested mutation.* It will pass only wild-type allele to its offspring. |
CARRIER |
Tested mutation was detected in animal with „carrier“ result. Animal tested as carrier has one wild-type and one mutation allele, it is in heterozygous state. It will not develop disease caused by tested mutation.* It can pass wild-type or mutation allele to its offspring. |
AFFECTED |
Tested mutation was detected in animal with „affected“ result. Animal tested as affected has two copies of mutation alleles affecting the gene. It is likely the animal will experience a genetic disorder due to this mutation.** It will pass only mutation allele to its offspring. |
*Test excludes only tested mutation but not possible unknown mutations or factors that can lead to similar condition/symptoms.
** Potential unknown mutations or multiple other factors can possibly affect the likelihood of experiencing a genetic disorder.
References:
Ainsworth, S., Carter, S., Fisher, C., Dawson, J., Makrides, L., Nuttall, T., Mason, S. L. (2015). Ligneous membranitis in Scottish Terriers is associated with a single nucleotide polymorphism in the plasminogen (PLG) gene. Animal genetics, 46(6), 707–710. https://doi.org/10.1111/age.12339
Mason, S. L., McElroy, P., Nuttall, T. (2012). Genetics of ligneous membranitis in a family of Scottish terriers. The Journal of small animal practice, 53(11), 668. https://doi.org/10.1111/j.1748-5827.2012.01309.x
Mason, S. L., McElroy, P., Nuttall, T. (2012). Ligneous membranitis in Scottish terriers. The Veterinary record, 171(6), 160. https://doi.org/10.1136/vr.e5382