The spectrum of orofacial clefting.

LEARNING OBJECTIVES After studying this article, the participant should be able to: 1. Describe the differing types of congenital clefting defects that extend outward from the perioral region. 2. Define the sites of anatomical disruption and deformities that these types of facial clefts cause. 3. Describe the cause and incidence, if known, of orofacial clefts and their inheritance/transmission risks. BACKGROUND Clefts of the orofacial region are among the most common congenital facial defects. The clinical presentation is usually that of a lateral cleft of the lip through the philtrum with or without extension through the palatal shelves. However, atypical forms of clefts with lip involvement also occur in a variety of patterns, some of which are embryologically predictable; others are not. METHODS An overview of the embryology, cause, and incidence of this diverse and interesting group of congenital orofacial clefts is presented. RESULTS Clefts involving the lateral upper lip; median upper lip; and oblique facial, lateral facial, and median mandibular regions are reviewed. CONCLUSIONS This review of orofacial malformations describes clefting anomalies that emanate from the mouth and lips. As the causes of orofacial clefts are better understood, it is becoming clear that a complex interplay between genetic and environmental variables causes these clefts. Future study of orofacial clefts will require increasingly sophisticated methods of elucidating these subtle interactions.