Frequently Asked Questions about the test for the Hypertrophic Cardiomyopathy Mutation
The FAQs are grouped by the following topics:
Questions about the testing procedure
Q: Is it okay to use the swab to obtain DNA from the mouth of a pregnant cat?
A: Yes, we believe it should be safe to carefully swab the mouth of a pregnant cat to obtain a DNA sample for testing. The confusion about this is likely due to the label which shows this cytology swab is also used by OB/GYNs on human patients (it should not be used on pregnant humans for OB/GYN purposes).
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. One reason 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 kitten be in order to be tested?
A: A 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 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 should also be separated from food for about 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. 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?
A: One DNA sample is all that is required to perform this test. Two samples with sufficient DNA may provide a cross checked result.
Questions about the science:
Q: Why should I have this test performed on my cat?
A: To determine whether or not your cat has the MyBPC mutation.
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, positive cats account for about 1/3 of the number of cats tested. This is a significant percentage to completely eliminate from the gene pool. Therefore, 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. For more information about this topic, please refer to a good book on genetics.
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 the MyBPC mutation?
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 Maine Coons and other cat breeds.
Q: How soon will you find another mutation that may cause HCM?
A: Not soon enough but we are giving it our best effort.
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 the MyBPC Mutation. 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 the MyBPC Mutation. 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 are the current statistics for cats returning a positive test result?
A: As of September 2006, 33.4% of all cats tested returned a Positive result. Of this percent, about 4% to 5% were Homozygous for the mutation.
Q: What cat breeds may be tested for the MyBPC Mutation?
A: Any cat breed may be tested for the MyBPC Mutation.
Q: What cat breeds have tested Positive for the MyBPC Mutation so far?
A: As of September 2006, only Maine Coons and their progeny have tested Positive for this mutation. One Siberian cat tested Positive Heterozygote and its pedigree was traced back to a Maine Coon. No other cat breed has yet tested Positive for this mutation.
Q: Is it more likely that a positive homozygous cat will develop HCM than a positive heterozygous cat?
A: We do not have the data to determine the answer to this question at this time.
Q: Are there cats that tested positive for the MyBPC mutation and never develop(ed) HCM?
A: We do not officially have record of this data. We have been told by cat owners that their older, Positive cats have never been diagnosed with HCM.
Q: Do all cats with HCM test positive for the MyBPC mutation?
A: No. There are likely other mutations that may cause HCM.
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.