Description: In HCM, primary strengthening (hypertrophy) of the left cardiac ventricle wall and the cardiac septum occurs. The cardiac wall hypertrophy may also be present thanks to other diseases, in that case, it is called secondary HCM, and it is most often a result of high blood pressure or some hormonal diseases. A mutation in the MYBPC3 (myosin binding protein C) gene may lead to the HCM phenotype development due to changing the function and structure of sarcomere proteins (the basic functional and structural unit of muscle fibers). A mutation in a different domain of the MYBPC3 protein was identified in the ragdoll breed than in the Maine Coon breed. In this case, the mutation is described as C to T substitution, which causes amino acid arginine to tryptophan change at the position 820 (R820W) (Meurs et. al. 2007). The symptoms that may accompany this disease can be a low physical activity (from reduced mobility to paralysis of the legs), breath shortness, cough, decreased appetite, syncope (short loss of consciousness). Hearth arrhythmias and cardiac murmur in various intensities can also be a result of changes in the heart muscle. The disease manifestation can start at any age but middle-aged males are affected more often than other individuals. A negative result from a genetic test as well as a cardiological finding does not guarantee that cats become ill with any other form of cardiomyopathy during their lifetime. The test reveals the specific A31P mutation. It cannot be excluded that HCM may be caused by another mutation that has not been identified yet.
Mutations A31P and R820W have been found mainly in purebred Maine Coon and Ragdoll cats and in cats of random breeds with HCM disease, where the incidence has increased with age. There is research on the linkage between genes and HCM in other breeds of cats.
Inheritance: autosomal dominant with incomplete penetrance
Mutation: c.2458C>T (R820W) in MYBPC3 gene
Sample: EDTA whole blood (1.0 ml) or 2 buccal brushes. For official purposes, the confirmation of identity by Veterinarian is recommended.
The analysis is suitable for the following breeds: Ragdoll
Notes: Cat without risk of development of HCM due to mutation R820W has genetic test result N/N (negative in both alleles). Cat in risk of development of HCM due to mutation R820W has genetic test result N/P or P/P (cat carries one or two mutant alleles). In the case of the P/P result, the disease shows more severe clinical symptoms than in the case of the N/P result. Mutation R820W in MYBPC3 gene is inherited as an autosomal dominant trait with incomplete penetrance of the disease in heterozygotes (Longer et al. 2013).