Frequency of ARVD/C
The true prevalence of ARVD/C is still to be determined, but it is likely to be an under recognized condition. In Italy, the prevalence has been reported as 1:5000 people, accounting for 20 percent of sudden deaths in young adults and 25 percent of cardiac sudden deaths among athletes. In one small study in the United States a frequency at autopsy of 0.55 percent among young adults with sudden cardiac death was reported.
Causes of ARVD/C
As yet, the causes of most cases of ARVD/C have not been identified. Familial cases of ARVD/C (due to the inheritance of a defective gene) account for at least 30 percent of cases, with autosomal dominant inheritance with reduced penetrance being the most common. In the remaining cases, it is believed to be due to an acquired etiology (e.g. virus infection) or to unidentified inheritance. The genes identified to date include the ryanodine receptor 2 (RYR2) and desmoplakin. A complex set of recessive disorders, Naxos disease (ARVD/C associated with palmoplantar keratoderma and woolly hair) and Carvajal syndrome (same as Naxos disease except affects LV), have been shown to be caused by homozygous mutations in plakoglobin and desmoplakin, respectively.