The R207W mutation takes fourfold longer and the R214W mutation takes twofold longer to reach maximal current compared to wild-type channels. Since the time-course of an action potential is shorter than the time required for mutant KCNQ2 channels to reach proper levels of inactivation these mutants are expected to lead to neuronal hyperexcitability.
The R207W mutation causes a fourfold increase in time to reach maximal current, while the R214W mutation results in a twofold increase. Since action potential duration is shorter than the time needed for mutant KCNQ2 channels to reach full inactivation, these mutations are expected to cause neuronal hyperexcitability.