Plakophilin-2 c.419C>T and risk of heart failure and arrhythmias in the general population.

A rare genetic variant in the desmosomal gene plakophilin-2 (PKP2) c.419C>T(p.(S140F)) has repeatedly been identified in patients with dilated cardiomyopathy (DCM) and arrhythmogenic right ventricular cardiomyopathy (ARVC). Whether this is a disease-causing variant remains highly controversial. We tested this hypothesis using three approaches. Initially, in a prospective study of 10 407 individuals from the general population, including 2688 who developed heart failure or arrhythmias during >14 years of follow-up, PKP2 c.419C>T was identified in 98 individuals (0.94%). PKP2 genotype was not associated with electrocardiographic or echocardiographic changes, or with plasma levels of probrain natriuretic peptide (all P≥0.05). In c.419C>T carriers versus non-carriers, multifactorially adjusted hazard ratios were 1.26 (95% confidence interval: 0.77-2.07) for heart failure, 1.40 (0.90-2.17) for arrhythmias, 1.15 (0.78-1.71) for end points combined, and 1.33 (0.98-1.80) for all-cause mortality. The cumulative survival as a function of age and PKP2 genotype was similar among carriers and non-carriers (P=0.14). Second, comparing 517 patients referred for genetic testing with 1918 matched controls, odds ratios as a function of c.419C>T genotype were 2.11 (0.50-8.99) for ARVC, 0.72 (0.16-3.28) for hypertrophic cardiomyopathy (HCM)/DCM, and 1.28 (0.46-3.54) for end points combined. Third, in in vitro studies cellular localization of plakophilin-2, plakoglobin, connexin-43, or N-cadherin were similar in cells transfected with wild-type or mutant plakophilin-2. In conclusion, combining epidemiological data, with data on patients referred for genetic testing for ARVC or HCM/DCM, and data from in vitro studies, PKP2 c.419C>T did not associate with heart failure, arrhythmias, or premature death, with ARVC or HCM/DCM, or with effects in vitro, suggesting that this is not a disease-causing variant.