A malocclusion is an incorrect relationship between the upper and lower jaws or misaligned teeth. It can result from genetic factors, environmental influences, and disturbances during craniofacial development. Several craniofacial anomalies like cleft lip/palate are related to errors in neural crest cell migration. Conditions like fetal alcohol syndrome are caused very early in development by ethanol exposure. Childhood injuries and muscle dysfunction can also influence jaw growth and cause malocclusions.