Recent studies reported causative de novo heterozygous missense mutations involving this channel in developmental diseases that include Zimmermann-Laband syndrome 1 (ZLS1, MIM #135500) [27–29], Temple-Baraitser syndrome (TMBTS, MIM #611816) [30–32], syndromic intellectual disability [33] and syndromic developmental delay, hypotonia and seizures [34]. This evidence concerns the gene KCNH1 and Zimmermann-Laband syndrome 1.