KCNH1 and Intellectual disability: Additionally, KCNH1 variants have also been linked to Temple–Baraitser syndrome and Zimmermann–Laband syndrome, both of which are characterized by features like nail dysplasia, facial dysmorphism, and intellectual disability, while Zimmermann–Laband syndrome are further associated with hypoplasia of distal phalanges (53, 54, 55, 56).