In Case 2, myokymia was initially considered to be unrelated to the epilepsy, but both might be explained by deletion of KCNA1. Effects of KCNA1 mutations, at least in some cases, are attributable to a dominant-negative mechanism [29]; the mechanism in Case 2, with a microdeletion, is not yet known. This evidence concerns the gene KCNA1 and epilepsy.