KCNH1 and Zimmermann-Laband syndrome: Consistent with this hypothesis, pathogenic variants in other members of the potassium channel superfamily (KCNH1 and KCNN3) were previously reported in the clinically related condition Zimmerman-Laband syndrome (ZLS), a phenotype combining gingival fibromatosis and terminal deficiency of the digits (loci ZLS1 and ZLS3, respectively).