The molecular mechanisms that control skin morphogenesis are complex and only incompletely understood. Aplasia cutis manifests with localized skin defects at birth and is a feature in various syndromes. Identifying the genes that cause these genetic skin conditions provides the opportunity to define novel regulators of skin morphogenesis. Recently, human genetic approaches have led to the identification of aplasia cutis–causing mutations in genes that have previously not been implicated to have an important role in skin biology. These findings reveal novel molecular mechanisms that are involved in skin formation during development.