Dilatative Kardiomyopathie DCM2 (Titin)

Affected dogs suffer from congestive heart failure or sudden cardiac death. Two genetic variants... more
Dilated cardiomyopathy is a disease of the heart muscle. Due to the disease, the left ventricle (the heart’s main pumping chamber) is enlarged, dilated and weak, so that the heart is not able to pump the blood effectively.

In the breed Dobermann, dilated cardiomyopathy is a widespread inheritable disease. Affected dogs suffer from congestive heart failure or sudden cardiac death. Ventricular tachyarrhythmia is a typical sign of DCM and can be diagnosed by an echocardiogram or electrocardiogram (ECG). Pedigree analysis indicates an autosomal dominant mode of inheritance. Two genetic variants have been identified to be associated with dilated cardiomyopathy: the DCM1 variant located in the PDK4 gene (provides energy to the heart) and the DCM2 variant located in the titin (TTN) gene (helps the heart to contract).

There is a highly variable penetrance of DCM in this breed which means that genetically affected dogs could also show very mild or even no symptoms during their lifetime. Besides to the genetic status, nutrition, the level of exercise and other genes seem to have an impact on the individual risk of the dog. Therefore, the genetic test helps to identify the DCM associated variants but gives no prediction which genetically affected dogs will show clinically relevant symptoms. Moreover, there could be some other, still unknown variants causing DCM in this breed. Even if a dog is tested free of both variants, regular clinical testing could be necessary.
Dogs carrying the DCM1 variant (alone) heterozygous or homozygous, are 10 times more likely to develop the disease than dogs without the variant, while 37% of the dogs with this variant will develop the disease. Dogs carrying the DCM2 variant are 21 times more likely to develop the disease, while 50% of the dogs with this variant will develop the disease. Dogs carrying both variants have the highest risk to develop DCM (30 times) and 60% of the dogs with both variants show symptoms. These dogs should be monitored regularly for signs of the disease so that medication could be provided if needed to slow down the progression of DCM.

The genetic test should help to reduce the prevalence of the known variants in the breed without reducing the gene pool. Therefore, heterozygous dogs carrying only one variant (DCM1 or DCM2) should not be excluded from breeding if there is no familial history of heart problems, but should be bred with dogs that are tested free for both variants. Breeding of homozygous dogs and mating carriers of one variant with carries of the other variant (DCM1 with DCM2) should be avoided, in order to reduce the risk of the puppies to develop the disease.
Тип наследования
autosomal dominant, variable penetrance
Длительность теста
1-2 weeks after arrival of the sample in the lab
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