Expanding spectrum of human RYR2-related disease: new electrocardiographic, structural, and genetic features.
BACKGROUND
Catecholaminergic polymorphic ventricular tachycardia is a disease characterized by ventricular arrhythmias elicited exclusively under adrenergic stress. Additional features include baseline bradycardia and, in some patients, right ventricular fatty displacement. The clinical spectrum is expanded by the 2 families described here.


RESULTS
Sixteen members from 2 separate families have been clinically evaluated and followed over the last 15 years. In addition to exercise-related ventricular arrhythmias, they showed abnormalities in sinoatrial node function, as well as atrioventricular nodal function, atrial fibrillation, and atrial standstill. Left ventricular dysfunction and dilatation was present in several affected individuals. Linkage analysis mapped the disease phenotype to a 4-cM region on chromosome 1q42-q43. Conventional polymerase chain reaction-based screening did not reveal a mutation in either the Ryanodine receptor 2 gene (RYR2) or ACTN2, the most plausible candidate genes in the region of interest. Multiplex ligation-dependent probe amplification and long-range polymerase chain reaction identified a genomic deletion that involved RYR2 exon-3, segregated in all the affected family members (n=16) in these 2 unlinked families. Further investigation revealed that the genomic deletion occurred in both families as a result of Alu repeat-mediated polymerase slippage.


CONCLUSIONS
This is the first report on a large genomic deletion in RYR2, which leads to extended clinical phenotypes (eg, sinoatrial node and atrioventricular node dysfunction, atrial fibrillation, atrial standstill, and dilated cardiomyopathy). These features have not previously been linked to RYR2.
Bhuiyan
Zahurul A
ZA
Department of Clinical Genetics, Academic Medical Centre, University of Amsterdam, The Netherlands. z.a.bhuiyan@amc.uva.nl
van den Berg
Maarten P
MP
van Tintelen
J Peter
JP
Bink-Boelkens
Margreet T E
MT
Wiesfeld
Ans C P
AC
Alders
Marielle
M
Postma
Alex V
AV
van Langen
Irene
I
Mannens
Marcel M A M
MM
Wilde
Arthur A M
AA
D000185:Actinin / Q000235:genetics; D000293:Adolescent; D000328:Adult; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology; D001283:Atrioventricular Node / Q000503:physiopathology; D002311:Cardiomyopathy, Dilated / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology; D002874:Chromosome Mapping; D004562:Electrocardiography; D005192:Family Health; D005260:Female; D017353:Gene Deletion; D005838:Genotype; D006801:Humans; D008297:Male; D010641:Phenotype; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics*; D012849:Sinoatrial Node / Q000503:physiopathology; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000235:genetics* / Q000503:physiopathology
C401401:ACTN2 protein, human; D019837:Ryanodine Receptor Calcium Release Channel; D000185:Actinin