Congenital Myasthenic Syndrome (Heideterrier Type)
Affected Genes: CHRNE
Inheritance: Autosomal Recessive
Variant(canFam6):
chr5:31844757-31844758 1 bp insertion G
Breed: Heideterrier
General Information: Congenital Myasthenic Syndrome (Heideterrier Type) is an inherited neuromuscular disorder in dogs characterized by muscle weakness and fatigue. This condition results from a genetic mutation that affects the transmission of signals between nerves and muscles. Dogs with two copies of the associated gene mutation are predisposed to Congenital Myasthenic Syndrome, which typically manifests in early puppyhood. Symptoms include generalized muscle weakness, exercise intolerance, difficulty swallowing, and episodes of collapse. These symptoms can lead to significant mobility issues and impact the dog's quality of life. Management of the condition often includes medications to enhance neuromuscular transmission and supportive care to manage symptoms, but there is no cure for the disorder.
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 of the specific gene associated with Congenital Myasthenic Syndrome (Heideterrier Type) can determine if a dog is a carrier of this condition. This disorder is inherited in an Autosomal Recessive manner, meaning that dogs must inherit two copies of the mutated gene, one from each parent, to develop the disease. Carrier dogs, possessing only one copy of the mutation, typically do not show symptoms but can pass the gene to their offspring. When two carriers are bred, each pup has a 25% chance of developing the disease and a 50% chance of being a carrier. Reliable genetic testing is crucial for informed breeding practices to eliminate this mutation from breeding lines, and breeding two carriers together is not recommended to avoid producing affected pups. Dogs that are not carriers have no increased risk of having affected offspring.
References:
Herder V, Ciurkiewicz M, Baumgärtner W, Jagannathan V, and Leeb T. Frame-shift variant in the CHRNE gene in a juvenile dog with suspected myasthenia gravis-like disease. Anim Genet. 2017 48(5):625.