Adult to mature onset
For autosomal recessive disorders, dogs with two copies of the variant are at risk of developing the condition. Dogs with one copy of the variant are considered carriers and are usually not at risk of developing the disorder. However, carriers of some complex variants grouped in this category may be associated with a low risk of developing the disorder. Individuals with one or two copies may pass the disorder-associated variant to their puppies if bred.
At risk dogs may show signs of this disease in their lifetime, although many will not develop the condition due to absence of additional risk factors.
Partner with your veterinarian to make a plan regarding your dog’s well-being, including any insights provided through genetic testing. If your pet is at risk or is showing signs of this disorder, then the first step is to speak with your veterinarian.
Lafora Disease, also known as progressive myoclonic epilepsy, is a late onset, progressive form of inherited epilepsy. Clinical signs may be first seen in dogs over 5 to 7 years of age. Episodes typically include myoclonus (brief, involuntary muscle jerks or spasms that can involve an individual or group of muscles) which may occur spontaneously or secondary to a trigger (such as noise, light, or sudden movement within the field of vision). Other clinical signs can include hypnic jerks (involuntary muscle spasms when falling asleep) and generalized seizures. Episodes are also reportedly more likely to occur when the dog is excited or nervous, and less likely when the dog is focused on an activity. Lafora Disease tends to advance over many years and can lead to other neurological deficits, such as ataxia (uncoordinated walking), vision loss, cognitive dysfunction, urinary and fecal incontinence, and changes in behavior. The Wisdom test for Lafora Disease is what is known as a linkage test. It does not directly test for the known Lafora variant, but provides a prediction based on nearby proprietary marker(s) in the DNA. The test therefore gives an indicator of genetic status. For full confirmation of genetic status, it is recommended that a direct test for Lafora Disease is performed at a provider such as Laboklin.
Treatment of Lafora Disease is dependent upon the severity of clinical signs. For dogs with known triggers, environmental modifications may help improve quality of life. One example is training a dog to wear goggles if the trigger is shown to be walking in sunlight. For dogs with frequent or moderate to severe signs, anti-seizure medications can be used. However, not all dogs will respond to traditional anti-seizure medications so consultation by a veterinary neurologist should be pursued, if one is not already involved. Due to the progressive nature of the condition, clinical signs paired with a declining quality of life may lead to euthanasia on grounds of welfare.
There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.
This genetic variant is considered a risk factor for Lafora Disease, an autosomal recessive condition known to occur in Basset Hounds, Beagles, and Dachshunds. Dogs with two copies of the variant are at an elevated risk for being diagnosed with this condition; however not all dogs with two copies of this variant will go on to develop associated signs. Additionally, the Wisdom test for Lafora Disease is what is known as a linkage test. It does not directly test for the known Lafora Disease variant, but provides a prediction based on nearby proprietary marker(s) in the DNA. The test therefore gives an indicator of genetic status. Prior to breeding, it is recommended to confirm genetic status with a direct test for Lafora Disease through a provider such as Laboklin. After confirmation with a direct test for Lafora Disease, mating pairs should be selected according to recommendations for an autosomal recessive disorder: A carrier dog with one copy of the causal variant can be safely bred with a clear dog with no copies of the causal variant. About half of the puppies will have one copy (carriers) and half will have no copies of the causal variant. Puppies in a litter which is expected to contain carriers should be tested prior to breeding. Carrier to carrier mating in dogs with the causal variant should be avoided as puppies with two copies of the causal variant (and at increased risk) could be produced.
Lohi, H., Young, E. J., Fitzmaurice, S. N., Rusbridge, C., Chan, E. M., Vervoort, M., … Minassian, B. A. (2005). Expanded repeat in canine epilepsy. Science, 307(5706), 81. View the article