BVA (The British Veterinary Association) Eye Scheme & DNA Testing Summary

Please note these are recommendations from the BVA

The Society Eye Test Rule requirements are found here


Summary from Professor Sheila Crispin and Dr Cathryn Mellersh

Eye testing: The BVA/KC/ISDS Eye Scheme as it relates to the Border Collie is based on the best available evidence of inherited eye disease in this breed. Currently three inherited eye diseases are listed and certified on the basis of an eye test (clinical examination): they are Collie Eye Anomaly (present from birth), Central Progressive Retinal Atrophy (Retinal Pigment Epithelial Dystrophy) and Primary Lens Luxation (both of which develop in later life). Other possible inherited conditions being investigated include: primary glaucoma, early onset cataract and progressive retinal atrophy.

DNA testing (laboratory examination): This determines the normal, carrier or affected status for CEA only.

It is wrong to suggest that there is a choice of either eye testing or DNA testing, the tests are complementary not interchangeable and whereas Eye testing can detect ALL the conditions listed above, as well as newly emerging conditions, current DNA testing can only detect CEA.
 

Professor Sheila Crispin MA VetMB BSc PhD DVA DVOphthal DipECVO FRCVS

Sheila lives on a small farm in Cumbria and is a Life Member of the ISDS. She has owned a succession of Border Collies (both ISDS-registered and non-registered) over the years, her involvement with the ISDS and ophthalmology started as a veterinary student in the late 1960’s, under the tutelage of the much missed and inspirational Dr Keith Barnett.
She has been Chief Panellist of the BVA/KC/ISDS Eye Scheme on three occasions and remains a member of the Eye Panel Working Party, she is a member of the Kennel Club’s Dog Health Group, its Breed Standards and Conformation Sub-Group and is Chairman of the Dog Advisory Council. Sheila has an international reputation as a comparative ophthalmologist and her clinical work and research have taken her all over the world. In 2013 she was honoured as the first recipient of a Lifetime Achievement Award in Ophthalmology by the British Association of Veterinary Ophthalmologists and awarded Life Membership of the British Small Animal Veterinary Association at its annual Congress in 2014.

Dr Cathryn Mellersh BSc PhD

Cathryn is Head of Canine Genetics at the Animal Health Trust, near Newmarket, and a geneticist of international reputation. She, too, owes a debt of gratitude to Dr Keith Barnett, who worked closely with Cathryn’s team at the Animal Health Trust. Whilst Keith was quick to recognise the potential of DNA testing, indeed he memorably once said - “DNA testing, the ultimate diagnosis” - this was not at the expense of eye testing; he knew full well that both were needed in studying inherited diseases of the eye in any breed. Clearly, eye examination is required to recognise the abnormality in the first place and is then used to chart any changes of appearance over time.

Cathryn has an excellent research record, particularly in identifying a range of inherited diseases of the eye in dogs and her vibrant and expanding research team has identified numerous mutations associated with inherited canine disorders and developed genetic tests that are relevant to many breeds of dog. Her research group currently has around 40 separate projects underway, most of which are aimed at improving or understanding the genetic basis of a specific inherited disorder in a specific breed. Cathryn is a member of the Kennel Club’s Dog Health Group, its Health Screening and Genetics Sub-Group and the Dog Advisory Council.


EYE TEST

1. Requirement: All adult dogs and bitches should be eye tested (clinical examination) and a certificate of eye examination issued before any resulting progeny can be registered. Eye testing of adults should take place prior to breeding; adults must be at least 18 months of age at the time of first examination for certification. The results of the eye test are recorded on the Certificate of Eye Examination as clinically unaffected or clinically affected. The disorders involved are Collie Eye Anomaly (CEA), Central Progressive Retinal Atrophy (CPRA), Primary Lens Luxation (PLL), or other hereditary disease(s) of the Border Collie that may from time to time be added to conditions certified under the Eye Scheme.

Note that information is collected for a range of eye conditions in the Border Collie, including a number of other possible inherited eye diseases; currently the potential inherited conditions being investigated include primary glaucoma, hereditary cataract and progressive retinal atrophy.

2. Recommendation: Litter screening of puppies to diagnose CEA (clinically affected) becomes discretionary and is used in conjunction with CEA DNA Testing (see Table). Note, however, that dogs clinically affected for CEA are easier to detect as puppies (between 5-8 weeks of age) than adults. Post natal development can obscure choroidal hypoplasia (the key diagnostic feature) in mildly affected dogs (the misleading description ‘Go Normal’ has been applied to such dogs). ‘Go Normals’ may look normal on eye examination as adults, but they are genetically affected.

3. Recommendation: It is recommended that any dog or bitch that has been used for breeding should have a second eye test and a certificate of eye examination issued, when it is over 8 years of age; a reduced fee is charged for older dogs and this examination can identify later onset inherited disease.


DNA TESTING FOR COLLIE EYE ANOMALY (to be read in conjunction with the Table)

4. Currently the only DNA test for a specific inherited ocular disorder in the Border Collie is that for Collie Eye Anomaly, which ‘detects’ choroidal hypoplasia, but not colobomatous defects. Other DNA tests will undoubtedly follow, so the ISDS needs a clear strategy of how it will make the best use of eye testing and DNA testing in tackling inherited diseases of the eye. DNA testing for CEA can be used strategically, as outlined in the table, the aim of the advice on eye testing and DNA testing is to avoid producing clinically affected dogs and, in the long term, to eliminate the CEA mutation from Border Collies in a cost effective manner and without reducing genetic diversity. The patent for CEA DNA testing rests with OptiGen in the USA and so the sample must be sent there; it will remain expensive until the patent comes off (estimated expiry date 20th October 2025).

Note that CEA is an autosomal recessive disorder which means that two copies of the abnormal gene (ie one copy from each parent) must be present in order for CEA to be apparent (CEA affected). If only one copy of the abnormal gene is present the animal is a carrier and no CEA is apparent, if no abnormal genes are present the animal is unaffected for CEA (normal).

DNA PARENTAGE TESTING

5. Recognition of the ‘hereditary clear’ status means some dogs will not need to be DNA tested and DNA testing can also be used to verify parentage of such dogs, if desired. There are no patent issues and, as the testing can be done in this country, rather than abroad, it is a relatively cheap test. The ISDS needs a clear strategy of how to make the best use of the ‘hereditarily clear’ status and parentage testing.

RECORDING THE STATUS OF EYE TESTS AND LABORATORY TESTS BY THE ISDS

6. The results for all tests should be recorded in an open register, maintained by the ISDS, in order to obtain a clear picture of disease prevalence in ISDS registered dogs and to ensure that there is no inadvertent reduction of genetic diversity within the breed.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 





Recommended
Matings that cannot result in clinically affected puppies and that will result in at least 50% unaffected (normal) dogs. There is no need to litter screen Recommended matings.
Acceptable
Matings that cannot result in clinically affected puppies but that could result in a litter that are all carriers. There is no need to litter screen Acceptable matings.
Unacceptable
Matings that could result in clinically affected puppies and litter screening needed.

Summary of requirements for litter screening

There is no requirement for puppies born from Recommended or Acceptable matings to be litter screened.

All puppies born from Unacceptable matings do need to be litter screened.

SagePay