Frequently Asked Questions about the HCM Genetic Mutation Predominantly
Found in Ragdoll Cats
The FAQs are grouped by the following topics
The Testing Procedure
The Science
Test Results
Outside Sources
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?
A. One DNA sample is all that is required to perform this test.
Two samples with sufficient DNA may provide a cross checked result.
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?
A. Not soon enough but we are giving it our best effort.
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?
A. No. There are likely other mutations that may cause HCM in
cats like Ragdolls.
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).
Last Edited: May 16, 2007 8:37 AM
