Hypertrophic cardiomyopathy is the most significant cause of heart failure and death in ragdoll cats. This disease is characterized by a marked thickening of the left ventricle (heart muscle mass). This increased muscular thickness determines a decrease in chamber diameters, meaning less blood will pass through the heart and, as a result your cat will have problems breathing, will eat less, will be lethargic and weak, will lose weight, suffer abdominal swelling, vomit more frequently, or will lose the ability to use its hind legs.
Cardiomyopathy is life-threatening for any cat but especially for ragdolls as usually they are pretty calm, lazy beings, making any initial symptoms much more difficult to spot. If a specific cause is identified and can be resolved, many (sometimes all) changes in the heart can be reversed. This only happens though in very rare occasions, usually ragdoll HCM being considered to be of an unknown cause (idiopathic HCM). Even in these cases a good treatment can alleviate the symptoms for a long period of time.
Recently a genetic cause was found for this idiopathic form of HCM – MYBPC3 gene (cardiac myosin binding protein C gene), the same causing a human variant of HCM. Each gene comes in ever organism’s genetic material in two copies; these copies can be identical (homozygous) or different (heterozygous). The ragdoll cats having a single copy of the defective MYBPC3 gene have a less severe outcome than the ones having two mutant copies. Some veterinary services already offer genetic testing for this gene, crucial for breeders as the frequency of these mutation is around 30%. Very important – if your cat has the gene, keep in mind that half of its offsprings will have it too; you shouldn’t use these cats in breeding programs if you don’t really have to.