KCNH1 and Zimmermann-Laband syndrome: Mutations in the human KCNH1 gene encoding the Eag1 (KV10.1; KCNH1) protein, an isoform of the Eag K+ channel, have been linked to two congenital neurodevelopmental diseases, the Temple-Baraitser syndrome (TMBTS) and the Zimmermann-Laband syndrome (ZLS), both of which are characterized by intellectual disability, facial dysmorphism, and hypoplasia or aplasia of nails and terminal phalanges [7–9].