Frequently Asked Questions
Click the tabs below for answers to frequently asked questions about juvenile Dilated Cardiomyopathy in Toy Manchester Terriers, genetic testing and current or past research activities.
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About Juvenile Dilated Cardiomyopathy
What is Juvenile Dilated Cardiomyopathy?
Juvenile Dilated Cardiomyopathy in Toy Manchester Terriers is characterized by the death of young animals (typically less than 12 months of age) as a result of a sudden and fatal arrhythmia. Genetic research has determined that the condition is caused by a mutation in a gene associated with potassium channel formation, which is an integral part of the process regulating electrical activity in the heart.
What causes JDCM?
Each beat of an animal's heart results from rhythmic contractions of the heart muscle. Those contractions are regulated by electrical signals resulting from the controlled flow of ions into and out of heart muscle cells through channels in their membranes. There are a number of different ions involved in this process (including sodium, calcium and potassium) and each one has a role to play in depolarizing or repolarizing the heart muscle cells so they contract regularly.
Juvenile Dilated Cardiomyopathy in Toy Manchesters is caused by a mutation in a gene governing one of the potassium channels involved in this process. Researchers theorize that the mutation interrupts the function of normal potassium channels, causing damage to heart tissue at the microscopic level. Over time, normal heart tissue is replaced by scar tissue, interfering with the heart's ability to conduct the electrical current needed to make it beat. The eventual result is a fatal arrhythmia (abnormal heart rhythm) leading to sudden death.
What are the symptoms of JDCM?
Affected dogs usually appear healthy with no signs of heart disease present before the sudden passing. The only external abnormality is that affected male puppies may have unilateral or bilateral cryptorchidism (undescended testicles on one or both sides). For a number of the puppies, their sudden passing occurred within a day of general anesthesia/surgery or exercise.
How do I know if my dog has JDCM?
Until the fatal arrhythmia happens, affected dogs appear healthy (even during vet exams) and behave like normal puppies. As a result, the only way to know conclusively if a dog or puppy may be affected by JDCM is to perform a test to determine their genetic status.
Is Juvenile Dilated Cardiomyopathy ever seen in Standard Manchester Terriers?
We do not know if the mutation exists in the Standard Manchester Terrier population at this time. Standard Manchester breeders who decide to test should clearly mark their samples as Standard Manchester Terrier.
Is Juvenile Cardiomyopathy ever seen in English Toy Terriers?
This is a complicated question. Cases of juvenile cardiomyopathy have been observed in English Toy Terriers, however all cases reported to this study have had pedigrees that include Toy Manchester Terriers. It is recommended that English Toy Terrier breeders with Toy Manchester Terrier behind their dog(s) test their breeding stock. It is also recommended that English Toy Terrier Clubs or individual breeders interested in determining whether the gene exists in the pure ETT population consider further investigation through testing.
Juvenile Dilated Cardiomyopathy in Toy Manchester Terriers is characterized by the death of young animals (typically less than 12 months of age) as a result of a sudden and fatal arrhythmia. Genetic research has determined that the condition is caused by a mutation in a gene associated with potassium channel formation, which is an integral part of the process regulating electrical activity in the heart.
What causes JDCM?
Each beat of an animal's heart results from rhythmic contractions of the heart muscle. Those contractions are regulated by electrical signals resulting from the controlled flow of ions into and out of heart muscle cells through channels in their membranes. There are a number of different ions involved in this process (including sodium, calcium and potassium) and each one has a role to play in depolarizing or repolarizing the heart muscle cells so they contract regularly.
Juvenile Dilated Cardiomyopathy in Toy Manchesters is caused by a mutation in a gene governing one of the potassium channels involved in this process. Researchers theorize that the mutation interrupts the function of normal potassium channels, causing damage to heart tissue at the microscopic level. Over time, normal heart tissue is replaced by scar tissue, interfering with the heart's ability to conduct the electrical current needed to make it beat. The eventual result is a fatal arrhythmia (abnormal heart rhythm) leading to sudden death.
What are the symptoms of JDCM?
Affected dogs usually appear healthy with no signs of heart disease present before the sudden passing. The only external abnormality is that affected male puppies may have unilateral or bilateral cryptorchidism (undescended testicles on one or both sides). For a number of the puppies, their sudden passing occurred within a day of general anesthesia/surgery or exercise.
How do I know if my dog has JDCM?
Until the fatal arrhythmia happens, affected dogs appear healthy (even during vet exams) and behave like normal puppies. As a result, the only way to know conclusively if a dog or puppy may be affected by JDCM is to perform a test to determine their genetic status.
Is Juvenile Dilated Cardiomyopathy ever seen in Standard Manchester Terriers?
We do not know if the mutation exists in the Standard Manchester Terrier population at this time. Standard Manchester breeders who decide to test should clearly mark their samples as Standard Manchester Terrier.
Is Juvenile Cardiomyopathy ever seen in English Toy Terriers?
This is a complicated question. Cases of juvenile cardiomyopathy have been observed in English Toy Terriers, however all cases reported to this study have had pedigrees that include Toy Manchester Terriers. It is recommended that English Toy Terrier breeders with Toy Manchester Terrier behind their dog(s) test their breeding stock. It is also recommended that English Toy Terrier Clubs or individual breeders interested in determining whether the gene exists in the pure ETT population consider further investigation through testing.
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About Genetic Testing
How is Juvenile DilatedCardiomyopathy inherited?
JDCM is inherited as a simple recessive gene. This means that both parents of a litter must be carriers (i.e., carry one copy of the mutation) in order for an affected puppy to be produced.
How do I test for JDCM?
A DNA test for Juvenile Cardiomyopathy is available commercially through the University of Minnesota's Canine Genetics Lab at a cost of $65 (USD) per test. Follow this link for information on testing. The test can be completed using a simple mouth swab. Blood samples may also be submitted if preferred.
Breeders wishing to test young puppies should note that cheek swabs cannot be submitted for unweaned puppies. Please refer to the University of Minnesota website for instructions on submitting blood samples or dew claws.
How much does testing cost?
The University of Minnesota offers testing for JDCM or Xanthinuria separately or together at a discounted rate. Bulk discounts are also available for four or more dogs. Prices below are current as of July 2016, however breeders should consult the University of Minnesota website to confirm current costs before proceeding with testing:
Individual Dogs
JDCM or Xanthinuria alone: $65.00 per dog
JDCM and Xanthinuria combined: $100.00 per dog
4 Dogs or More*
JDCM or Xanthinuria alone: $58.00 per dog
JDCM and Xanthinuria combined: $85.00 per dog
*To qualify for a bulk discount, samples for all four dogs must be sent together, listed under the same contact person with one bill going to only one individual. Please submit a form for each dog. You may wish to mark the top of the form as "1 of X" (i.e., for 4 samples, 1 of 4, 2 of 4, etc.).
How do I pay for my test?
Breeders in the United States may send a cheque along with their samples to pay for their tests. Those submitting samples from outside the United States should select the "Bill owner electronically" option. Once swabs are received, clients will be billed electronically. The University of Minnesota accepts electronic payment by Visa, Mastercard, Discover, and American Express credit cards as well as debit cards.
Do I need to order a test kit?
No. Please note that swabbing kits are not available for order from the University of Minnesota. Those wishing to test their dogs should purchase sterile swabs at their local pharmacy per the directions provided. Samples should be sent with the submission form provided on the University of Minnesota website. You do not need to pre-order tests.
Will this test work for English Toy Terriers?
Yes. The genetic test simply measures the presence or absence of the mutation and will work across not only all dog breeds but different species as well. We know, for example, that mutations in the same gene have been linked to heart issues in humans. When testing ETTs, please clearly mark samples as English Toy Terrier.
Are there any special requirements if I am sending a sample from outside the United States?
If you are sending cheek swabs, no special instructions are required. If you will be sending blood, semen or tissue samples, lease refer to the University of Minnesota's website for information on USDA Importation Documents.
If my puppy has two copies of the mutation is it 100% certain he/she will die?
As of July 2016, DNA from 14 Toy Manchester Terriers who died of JDCM have been tested and all had two copies of the mutation. Additionally, nearly 100 adult healthy Manchester Terriers were tested and none had two copies of the mutation. Thus, the disease may be fully penetrant, meaning that all dogs with two copies of the mutation develop JDCM.
How should I manage JDCM in my breeding program?
It is extremely important that breeders guard against loss of important genetic material, particularly in our small gene pool. Dogs that carry for JDCM will not experience any symptoms and can be bred to dogs clear of the mutation without producing any affected puppies. Under no cirumstances should dogs be eliminated from a breeding program based wholly on their genetic status as carriers of JDCM. Generally, breeders should aim to manage the disease over a number of generations rather than attempting to remove the mutation from their lines immediately. By considering JDCM as one factor in planning a breeding or selecting a puppy rather than the primary driver, breeders will maintain higher quality and may avoid unintentionally concentrating genes responsible for other genetic problems. Check out our Information for Breeders page for links to articles on how recessive genes are inherited and strategies for managing recessive mutations in a breeding program.
JDCM is inherited as a simple recessive gene. This means that both parents of a litter must be carriers (i.e., carry one copy of the mutation) in order for an affected puppy to be produced.
How do I test for JDCM?
A DNA test for Juvenile Cardiomyopathy is available commercially through the University of Minnesota's Canine Genetics Lab at a cost of $65 (USD) per test. Follow this link for information on testing. The test can be completed using a simple mouth swab. Blood samples may also be submitted if preferred.
Breeders wishing to test young puppies should note that cheek swabs cannot be submitted for unweaned puppies. Please refer to the University of Minnesota website for instructions on submitting blood samples or dew claws.
How much does testing cost?
The University of Minnesota offers testing for JDCM or Xanthinuria separately or together at a discounted rate. Bulk discounts are also available for four or more dogs. Prices below are current as of July 2016, however breeders should consult the University of Minnesota website to confirm current costs before proceeding with testing:
Individual Dogs
JDCM or Xanthinuria alone: $65.00 per dog
JDCM and Xanthinuria combined: $100.00 per dog
4 Dogs or More*
JDCM or Xanthinuria alone: $58.00 per dog
JDCM and Xanthinuria combined: $85.00 per dog
*To qualify for a bulk discount, samples for all four dogs must be sent together, listed under the same contact person with one bill going to only one individual. Please submit a form for each dog. You may wish to mark the top of the form as "1 of X" (i.e., for 4 samples, 1 of 4, 2 of 4, etc.).
How do I pay for my test?
Breeders in the United States may send a cheque along with their samples to pay for their tests. Those submitting samples from outside the United States should select the "Bill owner electronically" option. Once swabs are received, clients will be billed electronically. The University of Minnesota accepts electronic payment by Visa, Mastercard, Discover, and American Express credit cards as well as debit cards.
Do I need to order a test kit?
No. Please note that swabbing kits are not available for order from the University of Minnesota. Those wishing to test their dogs should purchase sterile swabs at their local pharmacy per the directions provided. Samples should be sent with the submission form provided on the University of Minnesota website. You do not need to pre-order tests.
Will this test work for English Toy Terriers?
Yes. The genetic test simply measures the presence or absence of the mutation and will work across not only all dog breeds but different species as well. We know, for example, that mutations in the same gene have been linked to heart issues in humans. When testing ETTs, please clearly mark samples as English Toy Terrier.
Are there any special requirements if I am sending a sample from outside the United States?
If you are sending cheek swabs, no special instructions are required. If you will be sending blood, semen or tissue samples, lease refer to the University of Minnesota's website for information on USDA Importation Documents.
If my puppy has two copies of the mutation is it 100% certain he/she will die?
As of July 2016, DNA from 14 Toy Manchester Terriers who died of JDCM have been tested and all had two copies of the mutation. Additionally, nearly 100 adult healthy Manchester Terriers were tested and none had two copies of the mutation. Thus, the disease may be fully penetrant, meaning that all dogs with two copies of the mutation develop JDCM.
How should I manage JDCM in my breeding program?
It is extremely important that breeders guard against loss of important genetic material, particularly in our small gene pool. Dogs that carry for JDCM will not experience any symptoms and can be bred to dogs clear of the mutation without producing any affected puppies. Under no cirumstances should dogs be eliminated from a breeding program based wholly on their genetic status as carriers of JDCM. Generally, breeders should aim to manage the disease over a number of generations rather than attempting to remove the mutation from their lines immediately. By considering JDCM as one factor in planning a breeding or selecting a puppy rather than the primary driver, breeders will maintain higher quality and may avoid unintentionally concentrating genes responsible for other genetic problems. Check out our Information for Breeders page for links to articles on how recessive genes are inherited and strategies for managing recessive mutations in a breeding program.
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About the JDCM Study
Is the JDCM Study finished?
With discovery of the mutation causing Juvenile Dilated Cardiomyopathy in Toy Manchester Terriers, the study's primary objective of identifying a way to test for the disease has been realized. The current research team, led by Dr. Eva Furrow at the University of Minnesota, is continuing work on a formal paper reporting the discovery and describing findings. It is hoped that this final paper will be published in 2017. In addition to this, the Canadian and American Manchester Terrier Club study leads will be organizing a random sampling of Standard Manchester Terriers to test for the presence of both the JDCM and Xanthinuria mutations in that population.
Is the study still accepting necropsies or tissue samples from deceased puppies?
No. The study is no longer seeking information on or tissue samples from deceased puppies. We are available to assist if you or your veterinarian have questions, however. Please contact the study liaison directly if you require additional information.
We raised a lot of money for this project. Were all of the funds used for genetic research?
We were very lucky that the search for the gene causing JDCM went much more quickly and smoothly than anyone could have imagined. As a result, we anticipate that some funds raised will be available for re-direction to other Manchester Terrier-related health projects. We are still dealing with current and anticipated costs associated with introduction of the test however and will not have exact figures until all related activities are complete.
Who is overseeing expenditures related to the JDCM study?
Fundraising efforts in 2015-2016 received a great deal of financial and in-kind support. Managing money raised efficiently and effectively was a primary concern for everyone involved and we were lucky enough to have help in this area from the Gold Country Manchester Terrier Club. Blossom Scott-Heim, a member of the GCMTC and AMTC, has graciously overseen accounting for moneys raised under the auspices and using the GCMTC's accounts. The ability to have an independent third party oversee expenditures has ensured that management of funds is completed with appropriate oversights.
With discovery of the mutation causing Juvenile Dilated Cardiomyopathy in Toy Manchester Terriers, the study's primary objective of identifying a way to test for the disease has been realized. The current research team, led by Dr. Eva Furrow at the University of Minnesota, is continuing work on a formal paper reporting the discovery and describing findings. It is hoped that this final paper will be published in 2017. In addition to this, the Canadian and American Manchester Terrier Club study leads will be organizing a random sampling of Standard Manchester Terriers to test for the presence of both the JDCM and Xanthinuria mutations in that population.
Is the study still accepting necropsies or tissue samples from deceased puppies?
No. The study is no longer seeking information on or tissue samples from deceased puppies. We are available to assist if you or your veterinarian have questions, however. Please contact the study liaison directly if you require additional information.
We raised a lot of money for this project. Were all of the funds used for genetic research?
We were very lucky that the search for the gene causing JDCM went much more quickly and smoothly than anyone could have imagined. As a result, we anticipate that some funds raised will be available for re-direction to other Manchester Terrier-related health projects. We are still dealing with current and anticipated costs associated with introduction of the test however and will not have exact figures until all related activities are complete.
Who is overseeing expenditures related to the JDCM study?
Fundraising efforts in 2015-2016 received a great deal of financial and in-kind support. Managing money raised efficiently and effectively was a primary concern for everyone involved and we were lucky enough to have help in this area from the Gold Country Manchester Terrier Club. Blossom Scott-Heim, a member of the GCMTC and AMTC, has graciously overseen accounting for moneys raised under the auspices and using the GCMTC's accounts. The ability to have an independent third party oversee expenditures has ensured that management of funds is completed with appropriate oversights.
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