Genotype-Specific Outcomes of Desmosomal Cardiomyopathies.

Abstract

Desmosomal gene variants (DGVs) have been associated with a diverse spectrum of phenotypic manifestations within arrhythmogenic cardiomyopathy, but data on genotype-specific outcomes are lacking. We investigated genotype-specific arrhythmic and heart failure (HF) outcomes in DGV carriers. This cohort study included consecutive patients referred for screening for desmosomal genes. Carriers of pathogenic and rare (allele frequency <10^-⁴) variants of uncertain significance were included. The arrhythmic end point was the occurrence of a life-threatening arrhythmic event, defined as sudden cardiac death, aborted cardiac arrest, or hemodynamically unstable ventricular tachycardia. The end-stage HF outcome was the composite of a fatal HF episode or cardiac transplantation. We included 533 DGV carriers (59% male; median [interquartile range] age, 39 [22-54] years) from 214 families: 503 of 533 (94%) had a single DGV (212 [40%] <i>PKP2</i>, 160 [30%] <i>DSP</i>, 97 [18%] <i>DSG2</i>, 34 [6%] <i>DSC2</i>) and 30 of 533 (6%) double DGVs. Overall, 83 of 533 (16%) experienced a life-threatening arrhythmic event (at age 40 [33-51] years), and 14 of 533 (3%) experienced end-stage HF (at age 57 [50-60] years). Multivariable analysis demonstrated that, compared with nonmissense <i>PKP2</i> variants, nonmissense <i>DSP</i> variants (hazard ratio [HR], 2.3 [95% CI, 1.3-4.1]; <i>P</i>=0.008), missense variants in hotspot domains in <i>DSP</i> (HR, 2.7 [95% CI, 1.2-6.2]; <i>P</i>=0.010) and <i>PKP2</i> (HR, 3.6 [95% CI, 2.0-6.5]; <i>P</i><0.001), male sex (HR, 1.7 [95% CI, 1.1-2.8]; <i>P</i>=0.021), and double DGVs (HR, 3.4 [95% CI, 1.7-6.9]; <i>P</i><0.001) were associated with a higher risk of a life-threatening arrhythmic event. Nonmissense <i>DSP</i> variants (HR, 5.0 [95% CI, 1.5-18.2]; <i>P</i>=0.009) and double DGVs (HR, 4.7 [95% CI, 1.0-19.3]; <i>P</i>=0.044) were also associated with increased risk of end-stage HF. Among carriers of DGVs, genotype was associated with arrhythmic and HF outcomes, with type and location of the variant further modulating the natural history.