Background
Mutations that are described and validated in one breed can also occur in other breeds. Often these are not published in scientific articles. The occurrence of these mutations in other breeds is determined by the laboratories who perform the tests.
Hypertrophic Cardiomyopathy (HCM) is known in virtually all animal species, including humans. HCM is the most common cause for heart failure in young adults, both humans and animal species. The heart failure is caused by a thickening of the heart muscle, which ultimately results in a loss of function of the heart. In several cat population the clinical risks have been associated with genetic mutations.
It should be noted that in humans with the same disease, there are many different genetic mutations which can cause this disease. Presumably, the situation is similar in cats. In the statistics currently available, approximately half of the Maine Coon cats, which have been diagnosed with HCM by echocardiography or necropsy have the HCM mutation. Obviously, the remaining half have HCM from other causes, probably other mutations. This means that the absence of a mutation in a cat does not mean that it will never develop HCM. Additional mutations will be identified that may be tested for as well. Cats that are positive for the test will not necessarily develop significant heart disease and die from the disease. Some cats will develop a very mild form of the disease and will live quite comfortably, and some might even never develop any signs of the disease. It is not known at this time what makes one cat with the mutation develop HCM early, while another cat develops a much milder and later form, or no signs at all of any heart disease.
In humans, at least 10 mutations have been described, all resulting in HCM. In cats the first mutations have been found, but certainly more mutations in many breeds will be found in future research.
Validation by science
Various articles on HCM1, HCM2 and HCM3 have been published in the scientific world. By comparing the symptoms of a disease with DNA variations, a diagnostic test is verified, normally leading to publication in a scientific journal. Often, these articles are based on a single breed. In the scientific literature, when a test is published for the first time, researchers provide proof of the causal link between the mutations and the HCM disease. In a very recent article, the development of the HCM disease profile and diagnostics using ECGs was evaluated critically. It is known that the HCM disorder can be demonstrated microscopically in the cardiac muscles, but it is not always perceptible using an ECG.
Test specific information
This mutation for HCM3 is a genetic variant identified as R820W of the MYBPC3 gene (Ragdoll).
Several tests are available in different breeds. For the different mutations, clinical studies linking a mutation to HCM are not always available. It is up to the owner to decide which test to perform.
The first DNA test is available since 2006, for identifying cats with specific genetic mutations in the Myosin Binding Protein C 3 (MyBPC 3) gene. This mutation has been shown to be associated with HCM in a colony of Maine Coon cats.
At least two other mutations have been identified in 2007 and 2008, one of which was also found in the same MyBPC 3 gene. Each mutation should be ordered separately.
Age
The disease may show itself on different ages, in which it cannot be estimated when the first symptoms may show themselves. Differences may exist between littermates, and between breeds.
Throughput
Normally the result can be expected within 15 working days. This turn-around-time starts when both the sample and the fully filled-out and signed submission form have been received.
Location of disease or trait
This disease leads to a loss of heart function.
Breed dependence
This DNA test is available for the following breeds: Ragdoll.
Sample type
For this DNA test we accept the following materials: Blood EDTA, Blood Heparin, Swab, Tissue. Please contact PharmaDNA if you wish to submit other material as listed.
Result
If the result of a DNA test indicates that the animal is not the carrier of a mutation, this is not a guarantee that this animal will never develop HCM. The animal may also be a carrier of a gene that is not yet known and that has accordingly not been tested. If the results of a DNA test indicate that the animal is a carrier of or affected by a mutation, this is normally the basis for the assumption that the animal will develop HCM. Accordingly, there is a possibility that this mutation will be passed on to its offspring.
Inheritance
This genetic factor is inherited in an autosomal, dominant, mode. This means, that the individual can be free of the mutation (homozygote normal), affected (homozygous affected) or carrier (heterozygous affected). Both carriers and affected individuals will show symptoms of the mutation.
Severity of Disease
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