Desmin is an intermediate filament protein, which is linked to the desmosomes. Different DES mutations cause an abnormal aggregation of desmin and associated proteins. The penetrance is 20–35% in general, but significantly higher in Italy. Seven gene loci have been implicated in ACM. It is unclear whether the pathogenesis varies with the different loci involved. Standard genetic screening test are currently tested and evaluated in different state of the art cardiovascular research centres and hospitals. Types include:

Exercise-induced ARVC
In recent years, several studies have found excessive long-term sports activity to be a cause of exercise-induced arrhythmogenic right ventricular cardiomyopathy (EIARVC). For some athletes ARVC might develop due to high-endurance exercise and it most often develops without an underlying desmosomal abnormalities, possibly only as a result of excessive right ventricular (RV) wall stress during very high volumes of training, which is known to be causing a disproportionate remodeling of RV.In a 2003 study, 46 endurance athletes (mostly cyclists) presented with various symptoms suggestive of arrhythmia of RV origin. 59% of participants testing met criteria for ARVC and another 30% for possible ARVC. And only 1 athlete of the group had a family history of hereditable ARVC.Exercise-induced ARVC and athletes heart has an overlapping features. Pathogenesis
The pathogenesis of ACM is largely unknown. Apoptosis (programmed cell death) appears to play a large role. It was previously thought that only the right ventricle is involved, but recent cohorts have shown many cases of left ventricular disease and biventricular disease.
The origin of the ectopic beats is usually from one of the three regions of fatty degeneration (the "triangle of dysplasia"): the RV outflow tract, the RV inflow tract, and the RV apex. Signal averaged ECG (SAECG) is used to detect late potentials and epsilon waves in individuals with ACM. Echocardiography
Echocardiography may reveal an enlarged, hypokinetic right ventricle with a paper-thin RV free wall. The dilatation of the RV will cause dilatation of the tricuspid valve annulus, with subsequent tricuspid regurgitation. Paradoxical septal motion may also be present. MRI
Fatty infiltration of the RV free wall can be visible on cardiac MRI. Fat has increased intensity in T1-weighted images. However, it may be difficult to differentiate intramyocardial fat and the epicardial fat that is commonly seen adjacent to the normal heart. Also, the sub-tricuspid region may be difficult to distinguish from the atrioventricular sulcus, which is rich in fat. Cardiac MRI can visualize the extreme thinning and akinesis of the RV free wall. However, the normal RV free wall may be about 3 mm thick, making the test less sensitive. Angiography
Right ventricular angiography is considered the gold standard for the diagnosis of ACM. Findings consistent with ACM are an akinetic or dyskinetic bulging localized to the infundibular, apical, and subtricuspid regions of the RV. The specificity is 90%; however, the test is observer dependent. Biopsy
Transvenous biopsy of the right ventricle can be highly specific for ACM, but it has low sensitivity.