Cardiac arrhythmia

General Information: Cardiac arrhythmia caused by mutations in the QIL1 gene is a genetic disorder in dogs that affects the normal electrical activity of the heart. The QIL1 gene is crucial for the proper functioning of mitochondria, and mutations in this gene can disrupt the energy balance within cardiac cells, leading to irregular heart rhythms. This condition is inherited in an Autosomal Recessive manner, meaning that two copies of the mutated gene—one from each parent—are required for the dog to be affected.

Symptoms of cardiac arrhythmia can vary in severity and may include exercise intolerance, fainting episodes (syncope), and in severe cases, sudden cardiac arrest. The age of onset and progression of symptoms can differ, with some dogs exhibiting issues early in life and others developing problems later. Early detection through genetic testing and regular veterinary cardiac evaluations are critical for managing this condition.

How to Read Your Dog's Test Results for this Genetic Variant:

Two Variants Detected: Dog Likely Affected

One Variant Detected: Dog is a Carrier

No Variants Detected: No Effect

Gene / Testing Information: Genetic testing for the QIL1 gene variant can identify whether a dog is affected by or a carrier of cardiac arrhythmia. This disorder is inherited in an Autosomal Recessive manner, meaning that a dog must inherit two copies of the mutated gene to exhibit symptoms. Dogs with only one copy of the mutation are carriers and will not show symptoms but can pass the mutation to their offspring.

Dogs identified as carriers can be safely bred with dogs that have no copies of the mutation to avoid producing affected puppies. Breeding two carriers, however, will result in a 25% chance of affected offspring, a 50% chance of carriers, and a 25% chance of unaffected puppies. Responsible breeding practices and early genetic screening are key to managing the prevalence of this condition in dog populations.