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Laryngeal Paralysis and Polyneuropathy (Leonberger Type 3)

Laryngeal Paralysis and Polyneuropathy (Leonberger Type 3) is an inherited neurological disorder in dogs causing breathing difficulties, vocal changes, and mobility issues.

Affected Genes: CNTNAP1

Inheritance: Autosomal Recessive

Variant(canFam6):
chr9:19760217: C>T

Breed: Labrador Retriever
Leonberger
Saint Bernard
St. Bernard

General Information: Laryngeal Paralysis and Polyneuropathy (Leonberger Type 3) is a genetic neurological disease that affects dogs, typically presenting clinical signs before the age of 5. Affected dogs often exhibit symptoms such as difficulty breathing, characterized by a loud and harsh respiratory sound, difficulty swallowing, and changes in vocalization. In severe cases, dogs may experience uncoordinated gait, stumbling, tripping, exercise intolerance, and muscle deterioration. While some dogs can manage this condition with lifestyle changes, others may require surgical intervention to alleviate severe respiratory symptoms. The disease can lead to emergent respiratory distress or aspiration pneumonia, which may be fatal.

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 the CNTNAP1 gene is essential for identifying carriers and dogs affected by Laryngeal Paralysis and Polyneuropathy (Leonberger Type 3). This condition is inherited in an autosomal recessive manner, meaning a dog must inherit two copies of the mutated gene, one from each parent, to develop the disease. Carrier dogs, which have one normal and one mutated gene, typically do not exhibit symptoms but can pass the mutated gene to their offspring. Breeding two carriers is risky, as each puppy has a 25% chance of inheriting the disease and a 50% chance of being a carrier. Reliable genetic testing for the CNTNAP1 mutation allows breeders to make informed decisions, avoiding the mating of two carriers to prevent producing affected puppies. This practice is crucial for eliminating the mutation from breeding lines and ensuring the health and well-being of future generations. Although testing for the CNTNAP1 gene mutation reduces the risk of Laryngeal Paralysis and Polyneuropathy, there are other genetic causes of this condition. Therefore, a clear result for CNTNAP1 does not rule out the potential for similar diseases in a dog's lineage. Comprehensive genetic screening helps maintain the overall health and neurological function of dogs susceptible to this disorder.

References:
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 11(12):1426.