Arrhythmogenic cardiomyopathy phenotype associated with the pathogenic founder variant c.1211dup in PKP2
Authors: Bos T A , Piers S R D , Wessels M W , Houweling A C , Hoedemakers Y M , Bosman L P , Te Riele A S J M , Koopmann T T , Van Tintelen J P , Barge-Schaapveld D Q C M 
Published: November 2023

Abstract

Background
Arrhythmogenic cardiomyopathy results in life-threatening ventricular arrhythmia and heart failure. Phenotypic features vary according to genetic aetiology. Genotype-phenotype research is therefore crucial for patient counselling and treatment decisions such as implantable cardioverter defibrillator therapy. By collecting data from patient records we characterized the clinical phenotype associated with variant c.1211dup (p.Val406Serfs*4) in the plakophilin-2 gene (PKP2), common in the Dutch population.

Purpose
We aimed to investigate the incidence of ventricular arrhythmia and heart failure in families carrying the PKP2 c.1211dup variant. Furthermore, we aimed to determine the founder status of this variant, and compare phenotype severity with other truncating PKP2 variants.

Methods
Clinical data were collected retrospectively from medical records of 106 PKP2 c.1211dup heterozygous carriers (&gt;85% of known carriers in The Netherlands) in a Castor EDC database. Using occurrence of ventricular arrhythmia and heart failure, event-free survival was compared between males and females, and probands and family members, using log-rank tests. Using data from a central curated arrhythmogenic cardiomyopathy database, c.1211dup was compared to three other truncating PKP2 variants (c.235C&gt;T (p.Arg79*), c.397C&gt;T (p.Gln133*) and c.2489+1G&gt;A (p.?)) on ventricular arrhythmia-free survival by a Cox proportional hazards model, corrected for sex and proband status.

Results
Forty-seven carriers (44%) were diagnosed with arrhythmogenic cardiomyopathy at 41 years on average. As shown in figure 1, 29 participants (27%) experienced episodes of ventricular arrhythmia and 12 (11%) developed heart failure, with male carriers showing significantly higher risks than females on both endpoints (p&lt;0.05). Based on available magnetic resonance imagery and echocardiographic data, 46% of carriers showed either right ventricular dilatation and/or dysfunction, and a substantial minority of 37% showed some form of left ventricular involvement. Both geographical distribution of carriers (figure 2) and haplotype analysis suggested PKP2 c.1211dup to be a founder variant originating from the South-Western coast of the Netherlands. Finally, a Cox proportional hazards model suggested significant differences in ventricular arrhythmia-free survival between four PKP2 truncating founder variants, including c.1211dup.

Conclusions
The PKP2 c.1211dup variant is a Dutch founder variant associated with a typical right ventricular-dominant arrhythmogenic cardiomyopathy phenotype, but also notable left ventricular involvement. Males were most susceptible to the frequent ventricular arrhythmia, and less frequent heart failure was observed in general. Finally, c.1211dup possibly leads to a more severe phenotype than other Dutch PKP2 founder variants.Phenotype onset stratified by sexGeographic distribution carriers