The commonest deformity of the palate is cleft palate, which is a result of faulty embryonic development in which the two sides of the newly-forming palate fail to fuse or only fuse in part. If the cleft extends the full length with bilateral clefts at the front of the maxilla, it may be accompanied by a cleft lip (also called hare-lip) and disruption in the development of the front teeth. About 1 in 500 babies is born with a cleft lip and 1 in 1,000 has a cleft palate. If the parents are affected, the risk is three times that of the normal population; if one child has a deformity, the risk for a subsequent child is higher. Associated abnormalities include tongue tie, malpositioning of the mandible and fluid in the middle ear.