Twelve different gain-of-function EAG1 mutations have been identified in twenty-two patients, in which five mutations are TBS-associated [23, 100], six mutations are ZLS-associated [21, 22], and four mutations are associated with atypical syndromes of ZLS/TBS as shown in Table 1 [24, 50]. The gene discussed is KCNH1; the disease is Zimmermann-Laband syndrome.