R784W
(LQT-2)
- back to mutations table -
KCNH2 cartoon -
| Voltage dependence of tail current | Current density of tail current @-40mv | Expression System | Other | Reference |
|---|---|---|---|---|
| WT 1.5±0.8 mV |
W.T. 37.6±6.1 pA/pF |
CHO | dominant negative effect not tested | Yang et al 2002 |
| RW 14.8 ±0.4 mV |
RW 9.5 ±1.1pA/pF |
co-exp. with KCNE1 | ||
| Positive | 75% reduction |
COMMENTS ON IN VITRO DATA
R784W mutation has found in a patient with amiodarone-induced QT interval prolongation.
R784W has been identified in 1/92 patients with drug-induced Torsades de Pointes
by Yang
et al 2002, in a population-based study aimed quantifying the prevalence
of LQTS-related gene mutations in such group of patients. In vitro expression
showed that this mutation reduces IKr currents but do not abolish
them, thus suggesting a possible direct correlation with the mild clinical phenotype
similarly to KvR583C mutation. The presence of
a dominant negative effect was not tested. .