Assessment and Validation of a Phenotype-Enhanced Variant Classification Framework to Promote or Demote RYR2 Missense Variants of Uncertain Significance

Background: Many rare, potentially pathogenic, RYR2 variants identified in individuals with clinically definite catecholaminergic polymorphic ventricular tachycardia (CPVT) are classified ambiguously as variants of uncertain significance (VUS). We aimed to determine if a phenotype-enhanced variant classification approach could reduce the burden of RYR2 VUS encountered during clinical genetic testing. Methods: This retrospective study was conducted in 84 RYR2-positive individuals from the Mayo Clinic (MC; Rochester, MN) and validated in 149 RYR2-positive individuals from Amsterdam University Medical Center (AUMC; Amsterdam, NL). Using a newly developed diagnostic scorecard, the pre-test clinical probability of CPVT was determined for all RYR2-positive individuals. Each RYR2 variant was then re-adjudicated using a phenotype-enhanced American College of Medical Genetics (PE-ACMG) approach that incorporates new criteria that reflect the phenotypic strength associated with each individual RYR2 variant. Results...