Frequently Asked Questions about the HCM Genetic Mutation Predominantly Found in Ragdoll Cats
The FAQs are grouped by the following topics:
Questions about the testing procedure
Q: How do I get my cat tested for the predominantly Ragdoll MyBPC mutation
A: If you wish to test your cat for this mutation, you may submit your cat's DNA via cheek cells rubbed onto a sterile cytology swab and/OR blood drawn into a standard EDTA tube (purple top). These are the only two methods of DNA submission our lab is equipped to process. You may request a test kit, which includes one submission form and two cytology swabs for each cat to be tested. If you elect to submit blood draw, have your Veterinarian or Veterinary Technician draw between 0.5 to 1.0 ML of blood into a standard EDTA tube (purple top). Print the Submission Form found on our website. Two DNA samples (two swabs or two blood draws) allow us to cross check the test result.
Q: Is it better to submit DNA sample using a blood draw or a cheek swab?
A: We have no preference at this time. A swab with enough DNA sample works just as well in our testing process as blood draw. When we first began this testing process, it seemed that blood samples may have processed more easily than swab samples. Today, our procedure has matured and we typically see similar success for DNA extraction and testing process with both swabs and blood samples.
Q: Why do some tests return results faster than others?
A: There are several reasons for one sample to process faster to result than another sample. Perhaps the most common reason is that the swab(s) did not contain enough DNA to perform the test. Another reason for delayed results is that some DNA samples may not cooperate with our testing process as well as other samples. It may take several tries before one sample will finish the testing process through to clear result. Meanwhile, the other samples received at the same time processed easily. We do everything we can to achieve clear test results from DNA submitted and sometimes this means extra effort is required for certain samples.
Q: How old must a cat be in order to be tested?
A: A cat (kitten) has its own unique DNA that could be tested as early as one day after birth. The answer about timing depends on how the DNA sample is obtained. If a blood sample is desired, a veterinarian should be consulted to determine appropriate age of the kitten (cat) to yield between 0.5ml to 1.0 ml blood draw. If a cheek swab is desired, kitten should be weaned and separated from the dam about 24 hours prior to swabbing. The purpose in the separation from the dam is to reduce the likelihood that any of the DNA from the dam's teats is in the kitten's mouth. The mother's milk is not a factor. The skin cells from the dam's teats are the concern. Also, food particles on the cheek swab make it difficult to extract the DNA. The kitten/cat should also be separated from food for at least 1 hour prior to swabbing.
Q: What is the best way to submit DNA for kittens?
A: Swab or blood sample usually work equally well. The answer to this question depends on the choice of the submitter.
Q: My kitten may have had mother's milk in its mouth when I swabbed it. Will this affect the test result for this kitten?
A: Mother's milk is not a factor in cheek swabs from a kitten except to perhaps make the DNA extraction slightly more difficult. Mother's milk does not have DNA in it, per se, and it should therefore not contaminate the DNA sample from the kitten. The skin cells from the dam's teat(s) may present a DNA contamination in the kitten's mouth.
Q: My cat may have casually licked another cat before I swabbed its mouth. Will this mess up the test result for this cat?
A: We feel it is unlikely for there to be enough DNA from a casual incident like this to alter the test's result. There are no studies that support this sort of DNA transference.
Q: What are the most common errors that people make when returning swabs for testing?
A: These are the five most common errors:
Not enough DNA to perform the test.
Solution: Follow the instructions carefully and allow enough turns of the brush to accumulate enough cells. Note: You do not need to draw blood in order to get enough DNA on the swab, although blood on the swab is not a problem.
Not allowing the swab to air dry before sealing it into the sleeve.
Solution: If there is a great deal of moisture on the swab and it is sealed before drying, it may start to mold and mold will decrease the amount of DNA on the swab that we can work with.
Returning the swab into the sleeve with the brush side sticking out.
Solution: Always put the brush end of the swab inside first. The brush part is where the DNA resides (hopefully) after rubbing it inside the cat's cheek. So the brush end should be the most carefully protected part of the swab.
Not sealing the sleeve very well after the swab has been returned.
Solution: The swab should be returned into the paper-plastic sleeve and sealed closed with tape. There should be a very small gap or two when taping closed so the swab can get a little bit of air as this prevents mold from growing. But it is important to make sure the swab cannot be cross-contaminated with elements outside the sleeve.
Accidentally mis-labeling the swab sleeve with another cat's name.
Solution: Even the most careful submitter can mix up swabs. If you're doing multiple cats, try taking the swabbing process slow and careful. Be very organized. Give yourself a way to cross check which swab came from whom. If you swap one of the swabs, we'll likely know about it.
Careful consideration should be given to keeping each swab pristine before and after swabbing. We cannot provide clear, accurate results if the swabs were cross-contaminated prior to our receipt.
Q: What are the most common errors that people make when returning blood for testing?
A: There are four most common errors in blood submissions:
Not leaving enough room on the label for our lab to write data.
Not using a standard EDTA draw tube.
Not providing enough blood (0.5ml to 1.0ml – preferably closer to 1.0ml)
Overnight-ing the shipment on ice: this is not necessary because the fluid in the EDTA draw acts as a type of extender or preservative. Shipment should be priority but not necessarily overnight.
Q: Am I required to submit two DNA samples on the same cat in order to get a test result?
Questions about the science
Q: How was this mutation discovered?
A: Our laboratory discovered this mutation by comparing DNA from various Ragdoll cats.
Q: Why should I have this test performed on my cat?
A: To determine whether or not your cat has this MyBPC mutation associated predominantly with Ragdoll cats.
Q: Should responsible pet owners have their cat(s) tested for this mutation?
A: It is one of several tools available to responsible pet owners for monitoring the health of their cat(s).
Q: Should responsible breeders use this test in their cat breeding program?
A: This is one of many tools that a responsible breeder may use to help improve their breeding program.
Q: How many generations should be tested?
A: The answer to this question is dependent upon the breeder's own choice. Our test provides a result. The number of generations that should be tested will depend on both the test result(s) and the breeder's interpretation of this information.
Q: Do you advocate that all cats who test positive for this mutation be removed from the gene pool?
A: At this time, we advocate the well considered breeding of an otherwise breedworthy Positive Heterozygous cat to a breed-worthy Negative cat with the goal of testing their progeny to move forward with only Negative cats in the breeding program. We hope this test is one of many important considerations in a responsible breeding program.
Q: Will a Positive Heterozygous cat produce Negative progeny if bred to a Negative cat?
A: In theory, a Positive Heterozygous cat has a 50/50 chance of producing Negative progeny if bred to a Negative cat. Please study our breeder's helpful guide below.
Q: Are there other mutations that may cause HCM to develop?
A: There are believed to be numerous mutations that can cause HCM to develop in humans. We believe it may be the same with cats. This means yes, we believe there may be other mutations that may cause HCM to develop in cats.
Q: How many mutations may cause HCM to develop?
A: We do not have this information. We would like to have this information. This is the reason we continue our research.
Q: Do you track the heart health of all the cats you test for this MyBPC mutation associated predominantly with Ragdolls?
A: No. This is a task that would include too many variables that are outside of our control. This means tracking this information would not likely yield credible data.
Q: Does your laboratory still research to find other genetic mutations that can cause HCM?
A: Yes. We have fulltime staff that work to find other mutations that may cause HCM in Ragdolls and other cat breeds.
Q: How soon will you find another mutation that may cause HCM?
Questions about interpreting the results
Q: What are the possible test results?
A: There are three (3) possible results:
Negative for the mutation (normal/normal)
Positive Heterozygous for the mutation (normal/mutant)
Positive Homozygous for the mutation (mutant/mutant)
Q: What do the test results mean?
A: There are three (3) possible results and each has a different meaning
Negative result means your cat does not have this mutation. It may or may not develop HCM in its lifetime but it will not develop the form of HCM associated with this mutation.
Positive Heterozygous means your cat has one copy of this mutation (instead of two). It may or may not develop HCM in its lifetime but it is more likely to develop HCM than a Negative cat.
Positive Homozygous means your cat has two copies of this mutation (instead of one). It may or may not develop HCM in its lifetime but it is more likely to develop HCM than a Negative cat.
Q: My cat tested negative for this MyBPC mutation associated predominantly with Ragdolls. Does this mean this cat will never develop HCM?
A: Your cat will not develop the form of HCM associated with this mutation. However, your cat may or may not develop HCM in its lifetime.
Q: My cat tested positive for this MyBPC mutation associated predominantly with Ragdolls. Does this mean this cat will develop HCM?
A: Your cat is more likely to develop HCM than a Negative cat. However, your cat may or may not develop HCM in its lifetime. Your cat should be evaluated annually by a veterinary cardiologist because it is at an increased risk.
Q: What cat breeds may be tested for this MyBPC mutation associated predominantly with Ragdolls?
A: Any cat breed may be tested for the MyBPC Mutation associated predominantly with Ragdolls.
Q: What cat breeds have tested Positive for this MyBPC mutation associated predominantly with Ragdolls so far?
A: Only Ragdolls have tested positive for this mutation so far.
Q: Should I test my Ragdoll cat for the MyBPC mutation primarily associated with Maine Coons?
A: As of Spring, 2007, only Maine Coons and their progeny have tested positive for that mutation. However, if a Ragdoll is thought to have Maine Coon in its pedigree, it could be a good idea to test that Ragdoll for the MyBPC mutation that is predominantly found in Maine Coons.
Q: Is it more likely that a positive homozygous cat will develop HCM than a positive heterozygous cat?
A: Yes. In most cases, the Ragdoll cats with two copies of the gene mutation (homozygous) have a severe form of the disease and often show clinical signs including breathing difficulty (heart failure), sudden death or development of blood clots. Ragdoll cats with one copy of the gene mutation and one normal gene often show very mild signs late in life but sometimes can be more severely affected. It is important to understand that additional studies to evaluate all of the clinical aspects of this disease are pending. Q: Are there cats that tested positive for this MyBPC mutation associated predominantly with Ragdolls and never develop(ed) HCM?
A: We do not have official record of this data.
Q: Do all cats with HCM test positive for this MyBPC mutation associated predominantly with Ragdolls?
Questions about outside sources
Q: Is your lab affiliated with any commercial lab outside of the USA?
A: No. Our laboratory is a non-profit laboratory. We are not affiliated with any commercial laboratories.
These are basic genetics that can be learned from any good educational source on genetics.
Each cat has two alleles. The alleles may be normal or mutant. One of the cat's alleles will be passed onto its progeny. Therefore, each kitten acquires one allele from each parent.
Possible Variations of Result:
- Negative for this mutation: Normal / Normal
- Positive Heterozygous for this mutation : Normal / Mutant Also known as "having one copy of the mutation"
- Positive Homozygous for this mutation: Mutant / Mutant
Also known as "having two copies of the mutation"
Breeding Plan: Negative (normal/normal) to Negative (normal/normal)
Result: Each Negative parent must pass a normal allele. Therefore, all progeny should be Negative (normal/normal).
Breeding Plan: Negative (normal/normal) to Positive Heterozygous (normal/mutant)
Result: Negative parent must pass normal allele to progeny. Positive HET parent has 50/50 chance of passing either the normal allele or the mutant allele to progeny. Therefore, progeny has possibility of being either Negative (normal/normal) or Positive HET (normal/mutant). It is possible Positive HET parent may pass only one type of allele 100% of the time. Therefore, it is possible for the entire litter to have the same result.
Breeding Plan: Negative (normal/normal) to Positive Homozygous (mutant/mutant)
Result: Negative parent must pass normal allele to progeny. Positive HOMO parent must pass mutant allele to progeny. Therefore, all progeny should be Positive HET (normal/mutant).
Breeding Plan: Positive Heterozygous (normal/mutant) to Positive Heterozygous (normal/mutant)
Result: Each Positive HET parent has 50/50 chance of passing either the normal allele or the mutant allele. It is possible that each parent may pass a particular allele 100% of the time and never pass its other allele to its progeny. Therefore, any combination of result may be occur from this breeding. The theory is that 25% of the progeny may be Negative (normal/normal) AND 50% of the progeny may be Positive HET (normal/mutant) AND 25% of the progeny may be Positive HOMO (mutant/mutant). However, any combination may occur and this means it is possible for the entire litter to be any one of the three variations and the above ratio theory may not prevail.
Breeding Plan: Positive Heterozygous (normal/mutant) to Positive Homozygous (mutant/mutant)
Result: The Positive HET parent has a 50/50 chance of passing either the normal allele or the mutant allele but may pass only one type of allele 100% of the time. The Positive Homozygous parent must pass the mutant allele to each progeny. Therefore, there are only two types of progeny this breeding will produce: normal/mutant OR mutant/mutant. The theory is that this breeding will produce Positive HET (normal/mutant) 50% of the time and Positive HOMO (mutant/mutant) 50% of the time. However, it is possible to produce Positive HOMO (mutant/mutant) 100% of the time in this breeding.
Breeding Plan: Positive Homozygous (mutant/mutant) to Positive Homozygous (mutant/mutant)
Result: The Positive Homozygous parent must pass a mutant allele to its progeny. Therefore, all progeny from this breeding must be Positive HOMO (mutant/mutant).