Genetic testing for cats
Genetic testing, or DNA testing, describes a number of different types of tests that examine the DNA of the cat to determine whether particular genetic variants (mutations) are present and, hence, whether these can be passed on to offspring. For owners, genetic testing can be a way to learn more about their cat’s health or genetic make-up. Responsible cat breeders can use these tests to help select breeding pairs to reduce risks of some inherited diseases, and also to identify desirable characteristics they would like in the kittens. Your veterinary surgeon may use genetic testing to aid in disease diagnosis, or to help determine risks of disease development.
What kinds of tests are available?
Single-gene mutation tests look at the inheritance of specific genetic diseases (eg pyruvate kinase deficiency), or traits (eg some coat colours), for example. These are very effective at determining the risks of having or passing on diseases or traits to offspring, which can be informative. These tests are often used by breeders to help identify low or no-risk cats for a specific disease, when choosing cats for breeding. Disease risks can be effectively eliminated with responsible use of these tests over several generations.
Panel testing for health
This describes a number of different products, but they generally test for a number of single-gene mutations, and sometimes include profiling/parentage testing, and ancestry information. As the information from these testing panels can be very complex, it is beneficial to choose a provider that has excellent support and advice. Look out for products that are tailored to be breed-specific, provide good advice, and explain both the results and how to use them for breeding.
These tests can be used to determine the likely relationship between a queen, tom, and kitten. Occasionally there can be uncertainty over a kitten’s parentage (usually who the tom is) in cat breeding, and parentage testing can help to resolve this.
Profiling your cat is increasingly popular as a way of identifying a cat. A cat may have a microchip removed, or lost, but the genetic profile of a cat is permanent and cannot be changed.
Ancestry testing It is not currently possible to determine a cat’s breed by genetic testing. However, ancestry testing can help to determine the likely recent heritage of your cat. It is typically used by owners of mixed-breed cats or rescues, either out of curiosity or to help predict characteristics.
These genetic tests vary enormously, but most attempt to either give some idea of the genetic diversity of the kittens that could result from a specific mating, or as a way of investigating the genetic diversity within a breed. These tests are not able to identify specific disease or health risks, or guarantee that increasing diversity will improve the health of an individual cat. This is in part due to this test being an over-all estimate of genetic differences, and doesn’t necessarily make a distinction between undesirable and beneficial mutations. It is generally accepted that reduced genetic diversity within a breed population can lead to more genetic health issues, and hence this should be avoided.
Specialist and diagnostic tests
These can be any number of genetic tests that are most often suggested by a veterinary surgeon. There are genetic tests that can diagnose disease without invasive procedures, look at risks for certain cancers, susceptibility to bleeding disorders, age-related problems, and much more. These tests are often used as part of a wider health care plan to diagnose or treat a problem.
Which tests should be used?
Many responsible cat breeders use genetic tests that are recommended specifically for their breed. You can find out about what tests are recommended before breeding from your veterinary surgeon, breed clubs, the Governing Council of the Cat Fancy (GCCF), and your breeder. Health tests can be genetic/DNA tests, and clinical (physical examination) tests. When assessing a cat’s test results, it is important that you understand what the test results mean, not just that the test was performed. A cat advertised as being “DNA tested” can mean anything, and does not guarantee health! It also important to recognise that testing for specific genetic diseases means testing for specific, known genetic mutations, eg the known mutation causing hypertrophic cardiomyopathy (HCM) in certain breeds. A negative or clear result for the known genetic mutation means that the cat will not suffer from, or pass on, the known disease mutation. It does not mean that the cat will never suffer from heart disease, or indeed HCM due to another cause, eg secondary to hyperthyroidism.
Can DNA tests impact health?
What genetic tests can help with:
- Use before breeding to reduce risk of perpetuating known disease(s) with genetic tests (eg single-gene mutations). This has been very successful in dramatically reducing the prevalence of some single-gene mutations, eg polycystic kidney disease caused by the PKD1 mutation in Persian cats.
- Use as an aid for disease diagnosis, in conjunction with veterinary care.
- Use for predicting risks of disease(s) or other attributes (eg linkage tests, Late-onset diseases).
- Finding out about a cat’s ancestry or make-up.
- Predict the underlying genotype of some phenotypic traits (eg tests for coat colour, length, etc).
- Parentage testing.
- Diagnose all inherited genetic conditions in cats; if the genetic mutation has not yet been discovered it cannot be tested for.
- Inform you about non-inherited diseases.
- Tell you the age of disease onset, the severity of disease or the impact on welfare if your cat has a genetic disease.
- “Prove” your cat’s breed for GCCF registration.
- Treat a disease.
- Guarantee a cat’s “health”.
How can I access a test?
Owners can access genetic testing directly (called Direct-to-consumer testing), where in most cases an owner can order a DNA testing kit online, and provide a cheek-swab sample. For some tests, a veterinary surgeon will need to take a blood sample for submission and/or confirm the cat’s identity by its microchip number. There are also a number of tests that are accessed only through veterinary professionals, as they are either part of a wider diagnosis, or should be undertaken in conjunction with veterinary guidance and advice.
It is always recommended that any decisions about an individual cat’s health should be made with a veterinary professional’s advice.
Where can I get advice on genetic testing?
- For registered pedigree cats within the UK: The Governing Council of the Cat Fancy website (www.gccfcats.org/) has an array of free online health information resources that can help cat breeders to make informed breeding decisions: www.gccfcats.org/Health-Welfare/Genetic-Testing.
- Langford Vets, University of Bristol, UK: www.langfordvets.co.uk/diagnostic-laboratories/services/cat-genetic-testing/.
- UC Davis Veterinary Genetics Laboratory, California, USA: www.vgl.ucdavis.edu/services/cat/.