Lancashire Heeler health news
All the latest health news will be appear here updated by The Lancashire Heeler Club Health Sub Committee.
DNA TEST RESULTS ON THE KC WEBSITE
Lancashire Heeler PLL Carriers
DNA TEST RESULTS SUBMITTED BY Lancashire Heeler Community
Lancashire Heeler Eye test results
DNA Test Swab Kits
These will be available at Crufts and at LHC shows or you can order them direct from the AHT.
Eye Test Update
We will be looking at having eye testing at the Open Show in May being held at Roade. Look here for details of eye testing sessions .
Please note that from 1st January 2010 the Kennel Club require all dogs to be permanently identified by microchip or tattoo before being presented for eye testing.
Lancashire Heeler PLL Seminar
PLL SEMINAR – ANIMAL HEALTH TRUST - 18th FEBRUARY 2010
As we have now had a DNA test for PLL since October 2009 the Lancashire Heeler Club felt that there was a need for a seminar to answer the many questions that have arisen as a result of some anomalies intest results and to help breeders plan their future breeding programmes.
The research programme into PLL started over ten years ago and has been carried out by a collaboration of specialists at the AHT and Cambridge University, with funding from the Kennel Club Charitable Trust, The American Kennel Club Canine Health Foundation, Breed Clubs and individuals.
Dr Cathryn Mellersh, who lead the research, and Claudia Busse, an AHT Opthalmologist gave a talk on the genetics and clinical aspects of the condition. Dr Jeff Sampson, the Kennel Club Geneticist was also present and gave us some interesting information.
A brief overview of PLL was given with an explanation of what DNA is, what it does and how mutations in DNA cause inherited disease by passing down through generations. There are more than a dozen breeds which carry the PLL mutation. So far only one breed, the Shar Pei, has been found to carry a different mutation. This mutation could have started many years ago, even before the breeds had evolved to the different types we now know, making its way down through certain lines in different breeds/types, which is why breeds that appear totally unrelated carry the mutation.
DNA from affected and unaffected dogs was analysed to identify the region of the genome that was homozygous in all affected dogs and different in the unaffected dogs. The mutation was identified as a single nucleotide substitution in 2009. The DNA test was developed and made available in October 2009.
Clear dogs have two normal copies of the DNA the researchers are testing for. There may however be other causes, such as trauma or other unidentified mutations.
Genetically affected dogs have two copies of the mutation and will almost certainly develop PLL. To detect early clinical signs it is recommended that they are eye tested every six months from the age of eighteen months.
Carriers have one normal copy and one copy of the mutation. A small percentage of carriers (believed to be about 2.5%) go on to develop PLL. It is recommended that they are eye tested every six – twelve months throughout their lives.
To estimate the frequency of the mutation in Lancashire Heelers 98 samples were collected; full and half siblings were removed which left 46 samples, of which 28 were clear (61%), 17 were carriers (37%) and 1 was affected (2%).
Since October 2009 when the test was made available 256 Lancashire Heelers have been tested and the results show a remarkably similar result, in that 159 were clear (62%), 93 were carriers (36%) and 4 were affected (2%). This does not take into account the results for dogs whose samples had been submitted during the research period, although it has to be said that these might well have given a false impression of the numbers, as many of the samples were from known affected dogs or their immediate relatives, therefore having a higher percentage of carriers or affecteds. Over all the breeds 546 free test results have been given out for dogs whose DNA was supplied for the research.
In the case of just 23 dogs they were unable to give a DNA test result.
Advice from the specialists in the case of a recessive condition is that carriers should be mated to genetically clear dogs. It is not necessary to test all the puppies unless they are to be bred from. Breeds need to use carriers because the frequency of the mutation is so high.
Vitreal Leakage
As the zonules rupture, vitreous can leak into the anterior chamber of the eye. In some countries this is classed as a PLL 'failure' or PLL 'suspicious' and an affected diagnosis for PLL is given.
However, although many dogs with vitreal leakage will go on to develop PLL, vitreal leakage is not necessarily diagnostic of PLL. The Opthalmologists at the AHT explained that they would be looking for other signs, such as a wobble of the lens, or rupture of more of the zonules and would recommend further re-examination before making a diagnosis of PLL. A question was raised about vitreous strands in the anterior chamber, and Claudia replied saying that vitreous strands in the anterior chamber can be caused by an injury, such as a scratch and are not usually or necessarily a sign of PLL, but regular eye tests are needed to check there are no further developments.
It is likely that there is another mutation involved which may or may not be related to the one they have isolated, and until further research is undertaken they are not able to advise further at this stage. One other consideration is that carrier or clear dogs who themselves are the produce of an affected parent could be more likely to suffer full blown lens luxation themselves.
Research is ongoing to check dogs with vitreal leakage which have tested genetically clear of the mutation. Further samples are requested from carrier dogs who have gone on to develop vitreal leakage and from genetically clear dogs of over ten years of age who are still free from vitreal leakage.
The KC/BVA/ISDS Eye Panellists in the UK have a meeting on 28th April at which they will be discussing the subject of vitreal leakage, and Dr Sampson will be putting the case forward for classifying this as a separate condition to PLL, as under the current scheme in the UK any dog diagnosed with vitreal leakage is marked as being affected by PLL, which in some cases contradicts the genetic diagnosis of clear or carrier.
The general advice from the researchers is that they consider the DNA test to be 100% accurate for the mutuation being tested for, and breeders should continue to test and take notice of the results, using a genetically clear dog in any mating to ensure no genetically affected puppies are produced.
Advice on breeding from dogs with vitreal leakage was to also only mate them to a DNA tested clear, in case they were from the small percentage of carriers that become affected.
One other piece of advice given by Dr Sampson was to DNA test any dog to be used for breeding, even if declared 'hereditarily' clear by parentage, to avoid any possibility that a mix up had occurred such as a bitch being mated by two different dogs in one season, or even by the wrong dog without the breeder's knowledge. He felt the low cost of £40 for the test was a small price to pay for peace of mind.
Further updates will be given as soon as they are received from the Animal Health Trust.
Latest news from AHT
We are delighted that our DNA test for primary lens luxation is proving so useful to breeders - we have had an unprecedented response in the first few weeks of testing. Unfortunately, the level of response has been so great that our systems have been quite overwhelmed. We will be employing extra staff to cope with the demand, but that will take a few weeks to put in place. In the meantime, we would be grateful if clients could avoid contacting us unless it is really necessary. The current turnaround time for this test is about four weeks - however many of you will receive your results more quickly than that and we will endeavour to minimise the delay to clients as far as possible. Thank you for your patience.
Please ensure that all samples returned for DNA testing for PLL are taken using an AHT diagnostic sampling kit (obtainable free of charge from swabrequest@aht.org.uk, please quote number of kits needed and the test required). The only form we can accept for DNA Testing is headed "REQUEST FOR DNA TESTING". If you send in samples accompanied by forms headed "SAMPLE SUBMISSION FOR CANINE GENETIC RESEARCH" or "REQUEST FOR PRIMARY LENS LUXATION DNA RESEARCH RESULT" they cannot be processed and this can lead to long delays in dealing with your request.
OptiGen has a test available for Lancashire Heelers for CEA/CH. The next OptiGen 20/20 Clinic will be advertised here.
May 1st 2010
Border Collie Breed Council Open Day
- Moira, Derbyshire.
OPTIGEN CLINIC - 'live' for online ordering from April 15th to May 1st 2010. All of the samples using the code for this clinic MUST arrive at OptiGen in one package to take advantage of the full discount available. The code for this clinic is BCCBC1051 and will be 'live' on the OptiGen website for online ordering from 15th April through to 1st May.
Optigen 20/20 Clinic
The Lancashire Heeler Puppy co-ordinator can help you find Lancashire Heeler puppies or help with litter placement, providing club guidelines have been followed with matings.
