Genetic Diseases - What are they?(prelude)
In this article we will look at some common genetic diseases and understand (Swab)testing vs screening.
In later installments of the article we will explore their signs and symptoms in greater depth.
Genetic diseases are passed down from parent to child, some are visible at birth whereas others manifest later in life. For a genetic disease to manifest it occurs in one of these scenarios.
Both parents are carriers ; one parent is a carrier with the other an affected cat or both parents are affected. In certain diseases as long as one parent has it, all kittens will contract the disease.
Being affected by the disease does not mean that the disease is in its active stage. It just means that the disease has a higher possibility of manifesting. A cat or kitten that is a carrier will show no sign of the disease. A affected cat may never develop the disease.
We wish to emphasize very early in this article Diet , Nutrition and Lifestyle play as crucial a role as screening for the prevention of such diseases.
In certain instances, these diseases are found in kittens where one parent is a carrier and the other is unaffected or unaffected parents, reinforcing the importance of external environmental factors and their impact in triggering and transmitting disease.
It is not solely due to their genetics.
Check out this great article
by
Cats Only
Veterinary Hospital
So what is genetic test? Is testing the same as screening?
In short, most genetic tests involve using a swab provided to take a sample of your cat's DNA by swabbing the inside of their cheek for a few seconds. Such tests are very popular as it is now very accessible. Simply go onto a e-commerce website and you can order one for approximately $200-$300.
Companies selling these tests will give you a report citing what type of cat you may have and the genetic diseases they carry. However, these tests aren’t as accurate or useful as you may think. They are not equal to human pregnancy or diabetic tests where answers are as simple as yes or no. They give you a probability. These tests are only as good as their controls.
When selecting which test to purchase, keep in mind that an effect test has to have a large control group so that its sensitivity and representation is accurate. The control group should also span a large geographical area. Basing a test on a small location or a small sample group affects the results significantly and may present false positives or inaccurate negatives.
It is important to note that most of these test have been found by Researchers( writing in the journal Nature) to be based on small, underpowered studies, where neither their accuracy nor their ability to predict health outcomes has been validated.
Such tests are not the same as screening at a vet using blood samples and scans. Screening is non breed specific and is done by reading of various data points to ascertain if a cat or kitten is displaying signs of a disease or developing one.
As swab test are not validated, the only real reference you have on your cat’s breed is proper record keeping by an association or registry. Once you have more information on the history of a domestic cat and you’ll see why only a pedigree ( record of breeding and heritage) will assist in clearing up doubts when it comes to cat breeds.
Seal Lynx point Siberian - out on a walk.
Majority of the modern domestic cat evolved from 2 main species, one from southwest Asia and into Europe and the other from African cats that dominated Egypt which spread into the Mediterranean. Some of these cats subsequently reached isolated land parcels and developed naturally. They formed distinct features and characteristics as well as their resulting collective DNA signature of that region and breed.
These landrace breeds are sufficiently distinct in their DNA patterns that allow for breed specific genetic determination.
The accepted landrace breeds are ( but not limited to these 25) :
Aegean | Abyssinian |American Shorthair |Arabian Mau| British Shorthair | Cyprus Cat | Dragon Li | Egyptian Mau | European Shorthair |
Japanese Bobtail | Khao Manee | Kurilian Bobtail | Korat | Main Coon | Manx | Norwegian Forest | Russian Blue | Siberian Forest | Sokoke |
Thai | Traditional Persian |Turkish Angora |Turkish Van
The above list is not to be confused with color mutations or coat mutations or with their pedigree counterparts with the same name.
These landrace cats are isolated and have very little possibility of making it outside of their habitats. They have distinct personality and appearances. Landrace breeds are very rare.
Approximately 5% of the entire population of domestic cats are pedigree and an even smaller percentage from these landraced breeds
By reading up on them you maybe able to gauge the probability of your cat’s heritage from the above.
Today , should you visit their habitats, you may even be able to find feral populations. They are usually protected from export thou they maybe incorporated as Foundational cats once approved by various judges and proper health screening.
Most pedigree cats were developed / refined from wild hybrids or these landrace breeds by man into what they are today.
There are certain pedigrees that originate from a small breed pool or were repopulated from extinction by outcrossing the few foundational cat/s. Such breeds also allow for ease of identification of the breed and its inherent genetic markers.
For example, the BSH was outcrossed with Persians/ exotics to bring the breed back thus a pedigree BSH may not show as one on a genetic test.
There is a misconception that Pedigree Cats are more predisposed to Genetic diseases than moggies (domestic long and short hairs). This misconception was due to inbreeding or the use of certain popular breeds to achieve specific traits.
Here are some of the more common and important inherited disorders of all cats with higher prevalence in certain breeds and their relatives ( Source from international cat care ):
Hypertrophic cardiomyopathy( HCM) in Maine coon, Ragdolls
Polycystic kidney disease (PKD) in Maine coon, Persians, exotics, Himalaya, British Short and Long Hairs
Feline leukemia virus (FELV)
Feline immunodeficiency virus (FIV)
WinterForests Screens for the 4 diseases. There are no genetics test for HCM or PKD for Siberians as it was developed/ mapped specifically for other breeds where it has shown a genetic tendency.
There are certain diseases with a higher breed predisposition, there is however no genetic sequencing to identify the exact gene that causes it.
Examples of this include:
Feline orofacial pain syndrome
Diabetes mellitus in Burmese cats
Asthma in Siamese and related cats
Mediastinal lymphoma in Siamese cats
Pyloric stenosis or dysfunction in Siamese cats
Small intestinal adenocarcinoma in Siamese cats
Strabismus (squint, cross-eyed) in Siamese cats
Cat associations highly encouraged their members work to remove such issues from their lines.
Breeders do not breed cats that produce or show evidence of such symptoms or appearance. This is done as associations tweak breed standards. This better understanding of the implications of such disorders places a larger emphasis on a healthy presentation.
Any presentation of these disorders are penalized in a show environment.
Thus the current approach adopted by most show catteries is to work on improvements on a breed for the longevity and well being of the cat. This is why a conformation to show standards and genetic diversity are important when selecting a cat.
If you have done a swab test and your cat is determined as pre-disposed to a particular trait due to its breed, it is not something to despair over. It is not a guarantee that your cat will develop such issues. You should consult your vet for confirmation and adjust their diet and lifestyle in efforts to prevent the disease from manifesting.
We highly encourage, rather than a reactive approach to changing your cat’s lifestyle due to genetic disposition, to adopt a superior nutritional environment for your cat.
Giving it a good diet for its heart and kidney’s regardless of probability of inheriting a disease from its parents.
A kitten that is fed a nutritional profile that is lacking will eventually develop issues like muscle loss , skeletal deformation and kidney issues.
We encourage selecting a pedigree cat of good breeding when looking to purchase a pet.
Check with its breeder on their stance and practices before proceeding.
Do not get a '“pure breed’ cat. This is a sure fire way of saying this cat/ kitten is from cats that are not conforming to health and care practices set out by associations and trained breeders in animal husbandry.
A pure breed cat is not an unregistered pedigree.
Ensure that your pedigree is certified by a recognized cat association and where possible choose established cats as they would have a historical track record that may set your mind at ease.
The Adopt Don’t Shop campaign started by LCA (Last Chance For Animals) was not to discourage people from buying pets from registered kennels and catteries .
It was meant to stop pet stores from selling puppies and kittens from backyard breeders or mills. These puppies and kittens are almost always advertised as pure breeds, foundational or hybrids and are not registered or sanctioned by any pedigree registry or association.
Choose rescue kittens and puppies from shelters. They are not dissimilar to the puppies and kittens usually touted as pure breed by such shops. Being unregistered, you will have no knowledge if they were overbred and are usually done so without proper health screening or educational guidance.
Sadly with the success of the campaign, backyard breeders are now charging even lower fees guised as an adoption fee for their kittens. They now produce them in larger numbers and poorer conditions to scoot under the radar of authorities as they are now deemed as adopted or gifts with very little cost. The lack of resources result in the lack of proper nutrition, screening and care. Creating a recipe for disaster with even higher proportions of unhealthy and abandoned pets.
Adopt, rescue and donate to rescues and organisations when possible. This helps to appreciate their good work by paying it forward when you adopt a cat from them and free up space for them to help another cat or kitten in need. Neuter your kitten and cat early instead of having it produce a litter without proper screening.
Registered shelters and proper rescuers have funding by donors that have helped to off set many of the costs required to nursing a healthy kitten or cat. Such privileges are not enjoyed by the BYB. Any cat owner can attest, veterinary costs and a good diet for your cat is not cheap and removing a kitten or puppy from its mother before 14 weeks not acceptable by most registries and could result in the striking off or other disciplinary actions on the breeder.
In short, if you do not know your cat’s ancestry ( non pedigree), you could test for genetic diseases by way of a simple swab that you may get online. If you only had $300, between deciding to spend it on a swab test or bringing your pet in to see your vet for a good physical check and ultrasound. We would definitely choose going to the vet. Pick one that is experienced in handling your breed or a collective pedigree of cats as each breed has its specific indicators to look out for.
If your cat belongs to a breed group that is more disposed to certain disorders. The swab test’s findings may be inaccurate and a vet screening will be a more informed choice regardless of the breed.
There is no harm in doing a swab test and the results could prove fun and a lovely activity to do with your cat.
Vet’s have access to the relevant scientific test and methods and should be able to catch early onset or indicators of diseases more accurately than a swab kit. It is true that human errors maybe made but swab test kits have yet to withstand scrutiny by the animal care community.
Stay tunned for the next installment of this article where we look at what the genetic diseases are, how they manifest and possible prevention methods.