Hypertrophic cardiomyopathy is the most important cause of heart failure and death in ragdoll cats. This disease is characterized by a marked thickening of the left ventricle (muscle mass of the heart). This increase in muscle thickness determines a decrease in the diameters of the cavities, which means that less blood will pass through the heart and, consequently, your cat will have trouble breathing, will eat less, will be lethargic and weak, will lose weight, will suffer swelling belly, vomiting. more often, or it will lose the ability to use its back legs.
Cardiomyopathy is life-threatening for any cat, but especially for ragdolls, as they are generally quite calm and lazy beings, making the initial symptoms much more difficult to detect. If a specific cause is identified and can be resolved, many (sometimes all) changes in the heart can be reversed. However, this only happens very rarely, rag doll HCM is generally considered to be of unknown cause (idiopathic HCM). Even in these cases, good treatment can relieve symptoms for a long period of time.
A genetic cause for this idiopathic form of HCM was recently found – MYBPC3 gene (cardiac myosin-binding protein C gene), the same one that causes a human variant of HCM. Each gene comes in the genetic material of each organism in two copies; these copies can be identical (homozygous) or different (heterozygous). Ragdoll cats that have a single copy of the defective MYBPC3 gene have a less severe outcome than those that have two mutant copies. Some veterinary services already offer genetic tests for this gene, crucial for breeders since the frequency of these mutations is around 30%. Very important: if your cat has the gene, keep in mind that half of his offspring will also have it; You should not use these cats in breeding programs if it is not really necessary.