What is DCM1 ?

DCM is the most common acquired heart disease of adult dogs. The heart has two heavily muscled ventricles that pump blood away from the heart. This disease causes progressive weakening of the ventricles by reducing the muscle mass, which causes the ventricles to dilate. Dilated ventricles do not contract and circulate oxygenated blood well, which eventually leads to heart failure.

Phenotype: Dilated cardiomyopathy is a heart condition in which the muscles degenerate, causing the walls of the heart to become thin, resulting in reduced contractibility. This can lead to congestive heart failure.

Mode of Inheritance: Autosomal dominant with incomplete penetrance

Alleles: N = Normal, DCM1 = dilated cardiomyopathy 1 variant present, DCM2 = dilated cardiomyopathy 2 variant present

Breeds appropriate for testing: Doberman Pinscher

Explanation of Results:

• Dogs with N/N genotype do not have either of the known DCM variants.

• Dogs with N/DCM1 or N/DCM2 genotypes are at risk to develop cardiomyopathy. If two heterozygotes with the same mutation are mated, approximately 75% of the puppies are at risk of developing the disease. Dogs heterozygous for both variants, N/DCM1 and N/DCM2, are at greater risk to develop clinical symptoms relative to those with only one variant.

• Dogs with DCM1/DCM1 or DCM2/DCM2 genotypes are at risk to develop cardiomyopathy. All puppies produced from matings of dogs with either of these homozygous genotypes are at risk for developing dilated cardiomyopathy.

A single affected copy of either gene is necessary to develop symptoms, but not all dogs with DCM1, DCM2, or both mutations will develop the disease. Since a single copy of either mutation can increase the risk for disease, this trait is considered a dominant trait. However, since not all dogs with these mutations go on to develop disease, these mutations are thought to be incompletely penetrant. Other factors likely explain the incompletely penetrant nature of this disease, and studies to investigate additional genetic and non-genetic risk factors are ongoing. Recently it was noted that in a European Doberman Pinschers sample set, the DCM1 mutation was not as correlated with disease risk as it is in the original Doberman study cohort.

Penetrance refers to the likelihood that a clinical condition will occur when a particular genotype is present. A condition is said to show incomplete penetrance when some individuals who carry the pathogenic variant express the associated trait while others do not.

The PDK4 gene is specifically associated with Doberman Pinschers, although this is only one of the genes associated with DCM1 in Dobermans. It is an autosomal dominant gene, meaning that only one copy of the mutation is needed to increase the risk of developing the disease.

Gene name

PDK4

Inheritance type

Dominant

Source: 1, 2