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Congenital Myasthenic Syndrome (Old Danish Pointer Type)

Congenital Myasthenic Syndrome (CMS) (Old Danish Pointer Type) is an inherited neuromuscular disease that causes exercise intolerance in Old Danish Pointers.

Affected Genes: CHAT

Inheritance: Autosomal Recessive

Variant(canFam6):
chr28:1720123: G>A

Breed: Old Danish Pointer

General Information: Congenital Myasthenic Syndrome (CMS) (Old Danish Pointer Type) is a genetic neuromuscular disorder that affects Old Danish Pointers, typically presenting between 12 to 16 weeks of age. Dogs with CMS show signs of exercise intolerance, where they can initially run and play normally for 5 to 30 minutes but eventually exhibit progressively shorter strides, leading to collapse due to muscle weakness. This temporary paralysis is alleviated after a few minutes of rest, allowing the dog to recover and resume activity, though the symptoms recur with prolonged exercise. While the condition does not worsen over time, it significantly impacts the dog's ability to engage in extended physical activities.

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 Congenital Myasthenic Syndrome (Old Danish Pointer Type) targets mutations in the CHAT gene. This condition follows an autosomal recessive inheritance pattern, meaning a dog must inherit two copies of the mutated gene to develop the disease. Carrier dogs, possessing one copy of the mutation, 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. To manage and potentially eliminate CMS from breeding lines, it is crucial to perform genetic testing before breeding decisions are made. Avoiding the mating of two carriers helps reduce the risk of producing affected pups, ensuring healthier litters and supporting the genetic diversity and well-being of the breed.

References:
Flagstad A, Trojaborg W, Gammeltoft S. Congenital myasthenic syndrome in the dog breed Gammel Dansk Hønsehund: clinical, electrophysiological, pharmacological and immunological comparison with acquired myasthenia gravis. Acta Vet Scand. 1989 30(1):89-102.

Flagstad, A. A new hereditary neuromuscular disease in the dog breed "Gammel Dansk Honsehund". Genetic investigations. Hereditas 1982 96:211-214.

Proschowsky HF, Flagstad A, Cirera S, Joergensen CB, Fredholm M. Identification of a mutation in the CHAT gene of Old Danish Pointing Dogs affected with congenital myasthenic syndrome. J Hered. 2007 98(5):539-543.