,32 Of note, gain-of-function mutations in different potassium channels (KCNN3, KCNH1, and KCNK4) are responsible for syndromes (including Zimmermann-Laband) that share developmental delay and/or intellectual disability, coarse facial features, gingival enlargement, and hypertrichosis among other features.33 This evidence concerns the gene KCNK4 and hypertrichosis.