Common Symptoms
Laryngeal Paralysis and Polyneuropathy (Leonberger Type 3) is an inherited neurological disease affecting dogs. Affected dogs typically present with clinical signs at less than 5 years of age including difficulty breathing, often described as loud and harsh, difficulty swallowing, and changes in the dog’s vocalizations. In severe cases, a dog’s mobility may be affected by an uncoordinated gate, stumbling and tripping, exercise intolerance and muscle deterioration. In some dogs, this condition may be managed with conservative measures such as changes in lifestyle while others require surgical treatment to reduce severe respiratory signs. This condition may result in emergent respiratory distress or aspiration pneumonia which can be fatal.
Testing Tips
Genetic testing of the CNTNAP1 gene in dogs will reliably determine whether it is a genetic Carrier of Laryngeal Paralysis and Polyneuropathy (Leonberger Type 3). This disease is inherited in an Autosomal Recessive manner. This means that dogs 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 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 CNTNAP1 gene mutation. Reliable genetic testing is important for determining breeding practices. To eliminate this mutation from breeding lines and avoid the potential of producing affected pups, breeding of known carriers to each other is not recommended. Dogs that do not carry the mutation are not at increased risk of having affected pups. However, because there are multiple causes of laryngeal paralysis and polyneuropathy caused by mutations in other genes, a normal result in CNTNAP1 does not exclude these diseases in a pedigree.
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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Letko A, Minor KM, Friedenberg SG, Shelton GD, Salvador JP, Mandigers PJJ, Leegwater PAJ, Winkler PA, Petersen-Jones SM, Stanley BJ, Ekenstedt KJ, Johnson GS, Hansen L, Jagannathan V, Mickelson JR, Drögemüller C. A CNTNAP1 Missense Variant Is Associated with Canine Laryngeal Paralysis and Polyneuropathy. Genes (Basel). 2020 Nov 27;11(12):1426.
[PubMed: 33261176]
