R27C (A-FiB3)

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COMMENTS TO IN VITRO DATA

• KCNE2 encodes for potassium channel beta subunit (MiRP1) shown to co-assemble with the KCNH2 gene product (HERG) in order to recapitulate a fully functional IKr current, the rapid component of the delayed rectifier current (IK), a voltage-dependent channel playing a crucial role for phase three repolarization in myocardial cells.
• An arginine-to-cysteine mutation at position 27 (R27C) of KCNE2, the beta subunit of the KCNQ1-KCNE2 channel responsible for a background potassium current, was found in 2 of the 28 unrelated probands with lone atrial fibrillation.
• The mutation was present in all affected members in the two kindreds and was absent in 462 healthy unrelated Chinese subjects. The mutation had a gain-of-function effect on the KCNQ1-KCNE2 channel.
• Interestingly, the authors did not report any functional effect on the HERG-KCNE2 current.