Feline hypertrophic cardiomyopathy (HCM), characterized by left ventricular hypertrophy, is the most common heart disease in domestic cats. Causative mutations in MYBPC3 have been identified in Maine Coon cats and Ragdolls. Affected cats can appear clinically normal, or they can present with signs of arterial thromboembolism or congestive heart failure. A test is available for Maine Coon and Ragdoll cats. Affected cats can appear clinically normal, but left ventricular hypertrophy can be identified by ultrasonography. First signs appear in young adults or adults, although Ragdoll cats may have an earlier onset than other breeds. Clinical presentation can include signs of arterial thromboembolism, such as bilaterally painful, contracted hind limb muscles, bilateral hind limb ischemia, and pulseless rear limbs with blanched pads. Other affected cats present with signs of congestive heart failure and associated pulmonary oedema. Clinical severity may be correlated to genotype (heterozygous vs. homozygous for the causative mutation). Cardiac hypertrophy occurs in the absence of increased pressure or metabolic stimuli. Histologically, the cardiac muscle shows myofibrilar or myocyte disarray. The MYBPC3 mutations do not eliminate the protein, but reduce the amount present in cardiac muscle.

Inheritance: autosomal dominant - read more

Mutation: MYBPC3 gene   (Meurs et. al. 2005; Wess et. al. 2010; Meurset. al. 2007)

Genetic test: The method used for testing is extremely accurate and allows complete differentiation between affected animals, carriers and healthy cats. Testing can be done at any age.

Disease control: Because disease is autosomal dominant it will manifest itself in all animals carrying at least on mutated gene. Such heterozygous animals will show clinical signs that will decrease their quality of life. Because the disease has relatively late onset, diseased animals can have offspring that will have 50% chance of obtaining gene with mutation and therefore develop the disease, if heterozygous cat is mated with normal cat. So far homozygous animals carrying two mutations have not been found, suggesting such animals die of while developing. With the intention of eradication of the disease it is not advisable to breed diseased animals.

Sample: EDTA whole blood (1.0 ml) or buccal swabs. Detailed information about sampling can be found here.