Myotonia Congenita (Labrador Retriever Type)

General Information: Myotonia Congenita (MC) (Labrador Retriever Type) is a genetic musculoskeletal disorder affecting Labrador Retrievers, typically presenting as early as 8 weeks of age. Affected dogs exhibit a stiff-legged gait and may have increased respiratory sounds when excited. They often struggle with swallowing food and water and may collapse with a rigid body and extended limbs during episodes of intense activity or excitement. Despite these challenges, affected dogs usually recover quickly from collapses and may show improved mobility with regular exercise. These symptoms result from dysfunctional electrolyte channels in the muscles, which affect muscle contraction and relaxation. While dogs with mild symptoms can lead relatively normal lives, those with severe cases may require medical intervention, although treatment outcomes can vary.

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 Myotonia Congenita (Labrador Retriever Type) involves screening for mutations in the CLCN1 gene. This disorder is inherited in an autosomal recessive manner, meaning a dog must inherit two copies of the mutated gene to develop MC. Carrier dogs, which have one copy of the mutation, typically do not show symptoms but can pass the gene to their offspring. When two carriers are bred, there is a 25% chance of producing affected puppies and a 50% chance of producing carriers. Genetic testing is crucial for responsible breeding practices, allowing breeders to identify carriers and avoid mating them with other carriers. By ensuring that at least one parent in a breeding pair does not carry the mutation, breeders can reduce the risk of producing affected puppies, thereby promoting healthier litters and preserving the genetic health of the breed.