Loss- or gain-of-function of KCNQ1 results from abnormal changes in the expression of Kv7.1 and reduced or increased changes in IKs currents, ultimately leading to various cardiac arrhythmias [2], which demonstrates that the expression level of Kv7.1 in cardiomyocytes is a critical condition for its function. The gene discussed is KCNQ1; the disease is cardiac arrhythmia.