Hypertrophic cardiomyopathy Ragdoll type (HCM)
Feline hypertrophic cardiomyopathy (HCM), the most common heart disease in cats, is a clinically heterogeneous disorder which is characterized by progressive enlargement of the heart and thickening of heart muscle, particularly of the left ventricle. Affected cats may progress into congestive heart failure, thromboembolic events or sudden cardiac death. Sudden death has been noted in cats only a few years old although affected cats may live for 10 years or more before developing symptoms including exercise intolerance, fatigue, fainting, fluid collection in the lungs, abdomen, and limbs, or blood clots that arise in the heart and travel to the kidney, brain, or legs. Ultrasound screening is a common tool utilized by veterinarians to see this disorder, though it can be difficult to diagnose this condition.
No data are available on the prevalence of mutation in Ragdolls. Affected cats have an average age of diagnosis of 15 months compared to the reported age of diagnosis of 5–7 years for the general feline hypertrophic cardiomyopathy population. Cats homozygous for the mutation develop moderate to severe disease and most die of their disease at 4 years of age or less.
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