KCNQ1 and gingival overgrowth: With the identification of a recurrent (P369L) and a novel (V185M) KCNQ1 variant (Table A1) and our functional analyses, we confirm that specific heterozygous KCNQ1 missense variants cause KCNQ1-KCNE2 (Q1E2) channel gain-of-function and underlie a particular disorder characterized by gingival overgrowth with or without postnatal growth retardation [20].