Post date: Nov 29, 2013 3:35:26 PM
The Wirehaired Dachshund Club's Lafora Sub-committee presented this report at the Dachshund Breed Council meeting held on November 24th.
Background
The Kennel Club and Breed Clubs donated funds to subsidise a research programme aimed at developing a test that would identify those miniature wire haired dachshunds that are Affected, Carriers or Clear of Lafora Disease.
The Centogene laboratory could not successfully develop a robust and consistent test that would identify Carriers, although the saliva tests they did, could differentiate between Affected and Unaffected animals.
Dr Minassian at the Toronto Hospital For Sick Kids had successfully developed a test for LaforaDisease in Children and had used similar techniques to develop a test for dogs. When we told him about the issues we were having, he used his Research Assistant to work on developing a test that could successfully identify Clear, Carriers and Affecteds.
The first batch of 41 blood and saliva samples was sent in April 2012. These tests took months to complete because of the complexity of the analysis and the risks of sample contamination.
Therefore, before the next batch was sent in April 2013, Dr Minassian’s team revived a previously used method that proved to be very successful and a lot quicker,he calls this the “Southern Blot” method. It remains extremely complex and is not a quick turnaround test.
The next batch of 46 was sent in April 2013 and by now it was apparent that saliva samples did not consistently offer robust results so just blood samples were sent. These results were turned round in approximately 10 weeks.
The third batch was sent in July 2013.
To date, a total of 322 dogs have been tested. Of those, 174 are Unaffected from the Centogene tests (we do not know if any of these are Carriers as they have not had the full test). 149 dogs have had the full spectrum test and the results of these are:
Affected: 14 (9.3%)
Carrier: 54 (36.2%)
Clear 81 (54%)
From the total dogs on our database (322) there are 37 Affected, which is an overall incidence of 11.4%(slightly inflated due to testing of some animals known to be affected and used as control samples). Whichever testing method has been used, the incidence per cohort has usually been around 10%.
The fourth batch of tests were sent on Thursday 21st November. This was our biggest session so far and we sent 102 samples off to Canada for the test.
Breed Records Supplement Quarter 3 2013
Therefore 82 puppies are from “safe” matings that could not produce affected puppies, although only 13 of those will definitely be clear, the other 69 could potentially be Carriers. The other 103 puppies are from “unsafe” matings that could potentially produce Affected puppies.
Vet Presentation
A vet (Anthony Dennison) from Myerscough Veterinary Group in Lytham St Annes, held an evening seminar at the Tickled Trout in Preston on Wednesday 23rdOctober. He has a special interest in neurology and has experience of owning and treating Miniature Wire Haired Dachshunds with LaforaDisease. He outlined how the disease behaves, what to expect and how best to manage the variety of symptoms. Attendance was not high from the breeder community, there were 4 breeders present. There were 8 members of the veterinary profession that had come to learn more about Laforaand 3 people with Affected dogs who had come to learn how best to manage the condition.
It focused mainly on the management of symptoms but did give an extremely good overview of the way the body of a Lafora Affected dog cannot break down carbohydrates. As a result, they are then stored as crystals in nerve cells and eventually prevent the cells from doing their jobs properly, particularly in the brain, hence the external symptoms. He confirmed that if dogs are diagnosed as Affected, they will develop symptoms – the disease is present from birth – it just builds up slowly. He was very clear that in his professional opinion, affected animals should not be bred from for a number of reasons, including:
Lafora is present from birth, the build up begins immediately because the liver cannot do its job properly in breaking down and absorbing carbohydrates. Therefore, just because outward signs are not visible, there is still a lot wrong on the inside and the changes brought on by pregnancy, including hormone levels and additional stress, give the central nervous system more to cope with, which could unnecessarily speed up the progression of the disease.
He confirmed that Lafora disease speeds up the ageing process due to the cells not being able to function properly - again, the advice was, the less stress the better. There is more work being done through the Progression Survey which will help to inform us about the age at which symptoms present and the speed at which they progress.
There was also a talk from a nutroceutical company, which was interesting, about products that can help with cell repair and anti-ageing, aimed at Lafora dogs or other diseases.
We are hopeful that Anthony will deliver more presentations over the next 12 months to raise awareness and enable people to ask questions.
Progression Survey
Gill Key is carrying out a progression survey in conjunction with Dr. Clare Rusbridge, a canine neurologist. These are the results so far. It is an ongoing piece of work to monitor the onset and differing rates of progression:
The only WHDC TESTED dogs that are showing no symptoms are all younger than 5. In other words, it appears that ALL affected dogs will develop symptoms at some stage
Average age of onset for ALL dogs : 7.16
Youngest age of onset WHDC TESTED dog was 2.5 (next youngest 4.5) Also youngest symptomatic dog on database – could be other, non-tested younger dogs.
Oldest age of onset WHDC Tested dog was 9.
Oldest age of onset for ALL dogs: 12 (next oldest 10) Neither are tested, so may be other causes.
More than 80% owners say that their vet did not recognise Lafora when first presented
Symptoms reported range from myoclonus, grand mal and petit mal fitting, fly catching, stiffness,aggression, vision impairment, hearing impairment, confusion, dementia, panic attacks, incontinence
50% of owners recorded that the symptoms had had a life-changing or significant impact on daily living for themselves and or the dog.
12% recorded little or no impact.
The future
Funds are limited so there is only sufficient subsidy for approximately 100 more dogs
There is another testing day in Surrey in January, combined with a Neurology Seminar covering Lafora Disease and IVDD. Forms are available from Sue Holt Susan.Holt@talktalk.net or Nora Price laforatesting@mypostoffice.co.uk
We are in discussions with the Kennel Club about getting the test recognised
All owners of dogs identified as affected through the WHDC scheme have been invited to attend the current Laforadogs progression survey and it is anticipated that this will provide an extremely useful source of information on a continuous basis