Genetic basis of Dilated Cardiomyopathy in Dobermanns - is associated with multiple genetic variants. The 2nd variant (DCM2) is a mutation in the TTN gene (titin), which plays a key role in heart muscle contraction and elasticity. This variant is inherited in an autosomal dominant manner with incomplete penetrance, meaning a dog carrying one copy of the mutation has an increased risk of developing DCM but may not always show symptoms. The presence of the DCM2 variant alone confers a considerable risk (~50% of dogs with the variant develop DCM), but risk increases further if the dog also carries the DCM1 variant in the PDK4 gene. The DCM1 variant affects metabolic energy supply to the heart, while DCM2 affects the structural protein titin; both contribute to the disease’s complex genetic nature.
Pathophysiology - causes enlargement (dilatation) of the heart chambers and weakened heart muscle contraction, leading to heart failure and arrhythmias. TTN mutations in DCM2 directly impair sarcomere integrity and elasticity, disrupting normal heart muscle function. Disease presentation includes ventricular tachyarrhythmias, congestive heart failure, and sudden death.
Complications - leads to potentially fatal rhythm disturbances and progressive heart failure. Sudden cardiac death can occur in seemingly healthy dogs. Quality of life declines with worsening cardiac function, necessitating lifelong management
Why This Matters to Breeders and Vets - Early identification of genetic risk allows breeders to make informed mating decisions to reduce disease prevalence. Veterinarians rely on genetic results along with clinical evaluations (echocardiograms, ECG) to monitor at-risk dogs proactively. Genetic knowledge helps predict disease onset but does not guarantee disease expression due to incomplete penetrance and environmental modifiers.