Genetic basis of Dilated Cardiomyopathy in Schnauzers - is caused by a 22-base pair deletion mutation in the RBM20 gene. This deletion leads to a frameshift and premature stop codon, resulting in a non-functional RBM20 protein, an RNA-binding protein involved in regulating mRNA splicing for genes critical in cardiac muscle function, including titin (TTN). The disease is inherited in an autosomal recessive pattern, meaning dogs must inherit two copies of the mutation (homozygous) to be at risk of developing DCM. Heterozygous dogs are carriers but typically do not show disease symptoms
Pathophysiology - The mutation disrupts intracellular calcium handling and cardiac muscle function through aberrant splicing of critical cardiac proteins such as titin. This leads to progressive weakening and dilation of the heart ventricles, impaired pumping ability, and arrhythmias. Clinical signs often manifest between 3 months to 3 years of age, with an average diagnosis around 1.6 years
Complications - leads to heart failure, arrhythmias, syncope, coughing, exercise intolerance, and increased risk of sudden cardiac death. Lifespan of affected dogs is significantly reduced, often by 80% compared to unaffected animals. Cardiac enlargement and decreased contractility can result in fluid accumulation, respiratory distress, and other serious complications
Why This Matters to Breeders and Vets - Early identification through genetic testing allows breeders to reduce disease prevalence. Veterinarians use genetic data alongside clinical screening (echocardiograms, ECGs) to identify at-risk Schnauzers early and manage disease progression proactively. Awareness helps avoid sudden cardiac death and improves quality of life through timely intervention
