Dilated Cardiomyopathy (DCM) in the Manchester Terrier

Dilated cardiomyopathy is a serious heart muscle disease that causes tissue in heart´s main pumping chamber to expand (dilate) and thin out. This makes it unable to pump  as strongly as it should. It is manifested by fatigue, general weakness and shortness of breath and usually leads to sudden death of juvenile affected dogs, typically by 6 months of age. Sometimes sudden death can occur without previous signs of disease.

In Manchester Terriers, the disease is caused by a missense mutation c.3557G>A in the ABCC9 gene, which encodes a regulatory subunit of potassium channels that play an important role in the regulation of electrical activity and metabolic responses in heart and smooth muscle.

The mutation is inherited in an autosomal recessive manner, meaning dogs need to inherit two copies of the mutated gene (one from each parent) to be affected. Carriers of the mutated gene are clinically healthy but pass the mutation on to their offspring. When two heterozygous individuals are mated, theoretically 25% of the offspring will be completely healthy, 50% of the offspring will be carriers and 25% of the offspring will inherit the mutated gene from both parents and will therefore be affected by the disease. The genetic test can clearly reveal the genotype of the animal and is a useful tool for breeders to avoid unintentional breeding of affected puppies.

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References:

Furrow, E., Tate, N., Minor, K., Martinson, S., Larrabee, S., Anttila, M., Sleeper, M., Henthorn, P. : An ABCC9 missense variant is associated with sudden cardiac death and dilated cardiomyopathy in juvenile dogs. Genes (Basel) 14:988, 2023. Pubmed reference: 37239348.