For example, frenum hyperplasia detected in a number of the patients of the present series was considered an important diagnostic finding in Ellis-van Creveld syndrome (caused by mutations in the EVC1 and EVC2 genes located on chromosome 4p16), which also share other oral manifestations with WHS such as peg-shaped teeth, agenesis, oligodontia, eruption delay, and microdontia [25]. Here, EVC2 is linked to Wolf-Hirschhorn syndrome.