KCNA3 and Prolonged QT interval: They included the Drosophila ortholog of the human potassium channel gene KCNJ2 (Irk1; Figure 6K)—the KCNJ2 mutation has been associated with long QT syndrome in human hearts [33]—as well as a voltage-gated channel gene (KCNQ; Figure 6K) that has been known to function in cardiac muscle contraction [34].