The RYR2-Encoded Ryanodine Receptor/Calcium Release Channel in Patients Diagnosed Previously With Either Catecholaminergic Polymorphic Ventricular …
A Medeiros-Domingo, ZA Bhuiyan, DJ Tester… - Journal of the American …, 2009 - jacc.org
A Medeiros-Domingo, ZA Bhuiyan, DJ Tester, N Hofman, H Bikker, JP van Tintelen…
Journal of the American College of Cardiology, 2009•jacc.orgObjectives: This study was undertaken to determine the spectrum and prevalence of
mutations in the RYR2-encoded cardiac ryanodine receptor in cases with exertional
syncope and normal corrected QT interval (QTc). Background: Mutations in RYR2 cause
type 1 catecholaminergic polymorphic ventricular tachycardia (CPVT1), a cardiac
channelopathy with increased propensity for lethal ventricular dysrhythmias. Most RYR2
mutational analyses target 3 canonical domains encoded by< 40% of the translated exons …
mutations in the RYR2-encoded cardiac ryanodine receptor in cases with exertional
syncope and normal corrected QT interval (QTc). Background: Mutations in RYR2 cause
type 1 catecholaminergic polymorphic ventricular tachycardia (CPVT1), a cardiac
channelopathy with increased propensity for lethal ventricular dysrhythmias. Most RYR2
mutational analyses target 3 canonical domains encoded by< 40% of the translated exons …
Objectives
This study was undertaken to determine the spectrum and prevalence of mutations in the RYR2-encoded cardiac ryanodine receptor in cases with exertional syncope and normal corrected QT interval (QTc).
Background
Mutations in RYR2cause type 1 catecholaminergic polymorphic ventricular tachycardia (CPVT1), a cardiac channelopathy with increased propensity for lethal ventricular dysrhythmias. Most RYR2mutational analyses target 3 canonical domains encoded by <40% of the translated exons. The extent of CPVT1-associated mutations localizing outside of these domains remains unknown as RYR2has not been examined comprehensively in most patient cohorts.
Methods
Mutational analysis of all RYR2exons was performed using polymerase chain reaction, high-performance liquid chromatography, and deoxyribonucleic acid sequencing on 155 unrelated patients (49% females, 96% Caucasian, age at diagnosis 20 ± 15 years, mean QTc 428 ± 29 ms), with either clinical diagnosis of CPVT (n = 110) or an initial diagnosis of exercise-induced long QT syndrome but with QTc <480 ms and a subsequent negative long QT syndrome genetic test (n = 45).
Results
Sixty-three (34 novel) possible CPVT1-associated mutations, absent in 400 reference alleles, were detected in 73 unrelated patients (47%). Thirteen new mutation-containing exons were identified. Two-thirds of the CPVT1-positive patients had mutations that localized to 1 of 16 exons.
Conclusions
Possible CPVT1 mutations in RYR2were identified in nearly one-half of this cohort; 45 of the 105 translated exons are now known to host possible mutations. Considering that ≈65% of CPVT1-positive cases would be discovered by selective analysis of 16 exons, a tiered targeting strategy for CPVT genetic testing should be considered.
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