Hope for Devastating Form of Epilepsy in Young Ridgebacks

I know last week I promised you another update on the 2016 Rhodesian Ridgeback World Congress – and pinky-promise, that’s coming – but today I want to share a group page that’s really blowing up on Facebook – and for all the right reasons.

Seemingly countless times a day, little pings from my phone and laptop tell me new members are being added to the fledgling Myoclonic epilepsy in rhodesian ridgebacks Facebook page. Last I checked, it was at almost 850 members.

Rhodesian Ridgebacks, like many dog breeds, can develop epilepsy: In the United States, the average age of onset for the breed is relatively late, usually around five years or six of age. But the form of epilepsy this Facebook page is devoted to appears much earlier, as young as six weeks, and as late as 18 months. Compared to “classic” epilepsy, this juvenile form is characterized by frequent muscle jerks or twitches, usually when the dog is sleeping or resting.

Videos of Ridgebacks having these shock-like seizures are quite heartbreaking: The poor dog is jarred and disoriented by the sudden episode, to say nothing of the traumatized owner.

“JME seems to run in many different lines,” explains Nina Lindqvist, founder of the Facebook group and chair of the Ridgeback club of Finland. “Therefore it is assumed that the mutation has already been in the breed for a very, very long time.”

Unfortunately, the long-term prognosis for juvenile myoclonic epilepsy, or JME, in Rhodesian Ridgebacks is not very promising. Dogs can be treated with a variety of anti-convulsive drugs: Levetiracetam (sold under the brand name Keppra in the U.S.), which was developed to treat myoclonic seizures in children, seems to work best, but its efficacy in dogs often cannot be maintained in the long term.

The good news is that European researchers have been busy studying the disorder: In 2015, Andrea Fischer at Munich University in Germany formally identified JME through clinical examinations, and Hannes Lohi’s Koirangeenit group at the University of Helsinki in Finland has isolated the recessive gene responsible for the disease.

Of the 538 samples analyzed by the Finnish researchers, 15 percent were carriers and 4 percent were affected. (And Nina notes that all dogs carrying two copies of the JME gene tested thus far are symptomatic – it appears dogs cannot dodge this genetic bullet.) Though the sampling was very likely skewed in favor of dogs likely to be carriers, the statistics are nonetheless sobering.

Anecdotal evidence suggests that this is a problem more prevalent in Europe and the United Kingdom. There were reportedly no American dogs sampled for the study.

Now that the causal mutation for JME has been identified, breeders are clamoring for a test, which is in the offing, but not until 2017, after the researchers’ studies have been peer reviewed and published.

Later this week, results of dogs tested for the research will be made available on the Ridgeback Club of Finland’s website at www.ridgeback.fi, contingent on the permission of their owners, of course. (There will be a link on the Facebook page, too.) Armed with that information, breeders can avoid breeding dogs with unknown genotypes to confirmed carriers to prevent any new affected dogs from being born.

Once the commercial test is available, Nina stresses that carriers may then be safely bred to confirmed clear dogs to prevent the disease from expressing while maintaining all-important genetic diversity. Remember: Carriers do not have the disease, and can only produce it if bred to another carrier.

Breeders who think they may have inadvertently bred two carriers can contact Nina at nina@lumottu.net. You can also contact her if you have a dog who was tested for JME and wish to have the results made public.

Everyone else, patience and crossed fingers until the commercial test is ready.