Experimental evidence suggests that altered muscular function can influence craniofacial morphology. The switch from a nasal to an oronasal breathing pattern induces functional adaptations that include an increase in total anterior face height and vertical development of the lower anterior face. While some animals studies have suggested predictable growth patterns may occur, studies in human subjects have been much more controversial. Therefore, individual variations in response should be expected from the alteration of a long face syndrome patient's breathing mode.