Among purebred dogs, the boxer has a particularly high incidence of inherited arrhythmogenic right ventricular cardiomyopathy (ARVC). Clinical and histopathologic characteristics closely mirror those seen in human ARVC. Clinically, ARVC is characterized by malignant ventricular arrhythmias, syncopal episodes, and sudden cardiac death. Histopathologically, the disease is defined by fatty or fibro-fatty replacement of the right ventricular myocardium, beginning in the “triangle of dysplasia” region and progressing from the epicardium to the endocardium. In advanced stages, lesions may encompass the entire right ventricle and extend into the interventricular septum and left ventricle.

In the boxer, where ARVC is highly prevalent, identifying a truly unaffected control group is nearly impossible. We suspect that many boxers previously classified as controls likely carried the causative genetic variant but were misclassified due to subclinical disease. As a natural ancestor of the boxer, the English bulldog offers a unique opportunity to overcome these limitations. Because ARVC is rarer in this breed, it is feasible to identify true control dogs using standard clinical tools such as echocardiography and 24-hour Holter monitoring. This allows clear distinction between affected and unaffected animals, providing the foundation for a powerful genetic comparison. The proposed work aims to elucidate the genetic mutation(s) responsible for ARVC in the boxer by tracing the disease to its likely ancestral origin in the English bulldog.