TY - JOUR
T1 - Transient outward current (I to) gain-of-function mutations in the KCND3-encoded Kv4.3 potassium channel and Brugada syndrome
AU - Giudicessi, John R.
AU - Ye, Dan
AU - Tester, David J.
AU - Crotti, Lia
AU - Mugione, Alessandra
AU - Nesterenko, Vladislav V.
AU - Albertson, Richard M.
AU - Antzelevitch, Charles
AU - Schwartz, Peter J.
AU - Ackerman, Michael J.
PY - 2011/7
Y1 - 2011/7
N2 - Background: Brugada syndrome (BrS) is a sudden death-predisposing genetic condition characterized electrocardiographically by ST segment elevation in the leads V 1-V 3. Given the prominent role of the transient outward current (I to) in BrS pathogenesis, we hypothesized that rare gain-of-function mutations in KCND3 may serve as a pathogenic substrate for BrS. Methods: Comprehensive mutational analysis of KCND3-encoded Kv4.3 (I to) was conducted using polymerase chain reaction, denaturing high performance liquid chromatography, and direct sequencing of DNA derived from 86 unrelated BrS1-8 genotype-negative BrS patients. DNA from 780 healthy individuals was examined to assess allelic frequency for nonsynonymous variants. Putative BrS-associated Kv4.3 mutations were engineered and coexpressed with wild-type KChIP2 in HEK293 cells. Wild-type and mutant I to ion currents were recorded using whole-cell patch clamp. Results: Two BrS1-8 genotype-negative cases possessed novel Kv4.3 missense mutations. Both Kv4.3-L450F and Kv4.3-G600R were absent in 1,560 reference alleles and involved residues highly conserved across species. Both Kv4.3-L450F and Kv4.3-G600R demonstrated a gain-of-function phenotype, increasing peak I to current density by 146.2% (n = 15, P to maximal conductance associated with the heterozygous expression of either L450F or G600R. Conclusions: These findings provide the first molecular and functional evidence implicating novel KCND3 gain-of-function mutations in the pathogenesis and phenotypic expression of BrS, with the potential for a lethal arrhythmia being precipitated by a genetically enhanced I to current gradient within the right ventricle where KCND3 expression is the highest.
AB - Background: Brugada syndrome (BrS) is a sudden death-predisposing genetic condition characterized electrocardiographically by ST segment elevation in the leads V 1-V 3. Given the prominent role of the transient outward current (I to) in BrS pathogenesis, we hypothesized that rare gain-of-function mutations in KCND3 may serve as a pathogenic substrate for BrS. Methods: Comprehensive mutational analysis of KCND3-encoded Kv4.3 (I to) was conducted using polymerase chain reaction, denaturing high performance liquid chromatography, and direct sequencing of DNA derived from 86 unrelated BrS1-8 genotype-negative BrS patients. DNA from 780 healthy individuals was examined to assess allelic frequency for nonsynonymous variants. Putative BrS-associated Kv4.3 mutations were engineered and coexpressed with wild-type KChIP2 in HEK293 cells. Wild-type and mutant I to ion currents were recorded using whole-cell patch clamp. Results: Two BrS1-8 genotype-negative cases possessed novel Kv4.3 missense mutations. Both Kv4.3-L450F and Kv4.3-G600R were absent in 1,560 reference alleles and involved residues highly conserved across species. Both Kv4.3-L450F and Kv4.3-G600R demonstrated a gain-of-function phenotype, increasing peak I to current density by 146.2% (n = 15, P to maximal conductance associated with the heterozygous expression of either L450F or G600R. Conclusions: These findings provide the first molecular and functional evidence implicating novel KCND3 gain-of-function mutations in the pathogenesis and phenotypic expression of BrS, with the potential for a lethal arrhythmia being precipitated by a genetically enhanced I to current gradient within the right ventricle where KCND3 expression is the highest.
KW - Brugada syndrome
KW - Genetic diseases
KW - Ion channels
KW - Ito current
KW - J-wave syndromes
KW - Kv4.3 channels
KW - Sudden cardiac death
UR - http://www.scopus.com/inward/record.url?scp=79959921753&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79959921753&partnerID=8YFLogxK
U2 - 10.1016/j.hrthm.2011.02.021
DO - 10.1016/j.hrthm.2011.02.021
M3 - Article
C2 - 21349352
AN - SCOPUS:79959921753
VL - 8
SP - 1024
EP - 1032
JO - Heart Rhythm
JF - Heart Rhythm
SN - 1547-5271
IS - 7
ER -