Hypertrophic cardiomyopathy Maine Coon type (HCM)
Hypertrophic cardiomyopathy Maine Coon type is an inherited disease affecting Maine Coon cat breed. 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.
The Maine Coon (MC) cat is predisposed to HCM. The true prevalence within the breed is not known, however its frequency varies by geographic area. The prevalence ranges between moderately high in Germany (22%), Asia (30.9%) and North America (22.5% – 31.7%), to high in Italy and France (38.2% – 41.5%), to even higher in Australia -New Zealand (46.3%). A dominant mode of inheritance has been established in some breeds and a causative mutation in the myosin binding protein C gene has been identified in the Maine Coon breed specifically.
The Maine Coon heterozygotes (carriers) usually lack evidence of Hypertrophic cardiomyopathy Maine Coon type during the years at which they would most commonly be bred. Even homozygotes for the mutation (affected) might not have evidence of HCM until they are closer to middle-age. Consequently, echocardiographic screening, especially of young cats, should not be the sole diagnostic to identify HCM-potential cats since genetic screening is needed to identify cats with the HCM-associated mutations. At the very least Maine Coon breeders should genotype their cats to make sure they are not breeding heterozygous to heterozygous cats and thereby producing cats homozygote for the mutation.
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