Cleft lip and cleft palate
A cleft lip contains an opening in the upper lip that may extend into the nose.[1] The opening may be on one side, both sides, or in the middle.[1] A cleft palate occurs when the palate (the roof of the mouth) contains an opening into the nose.[1] The term orofacial cleft refers to either condition or to both occurring together. These disorders can result in feeding problems, speech problems, hearing problems, and frequent ear infections.[1] Less than half the time the condition is associated with other disorders.[1]
Cleft lip and palate
Hare-lip, cleft lip and palate
Feeding problems, speech problems, hearing problems, frequent ear infections[1]
Present at birth[1]
Usually unknown[1]
Surgery, speech therapy, dental care[1]
Good (with treatment)[1]
1.5 per 1000 births (developed world)[2]
3,800 (2017)[3]
Cleft lip and palate are the result of tissues of the face not joining properly during development.[1] As such, they are a type of birth defect.[1] The cause is unknown in most cases.[1] Risk factors include smoking during pregnancy, diabetes, obesity, an older mother, and certain medications (such as some used to treat seizures).[1][2] Cleft lip and cleft palate can often be diagnosed during pregnancy with an ultrasound exam.[1]
A cleft lip or palate can be successfully treated with surgery.[1] This is often done in the first few months of life for cleft lip and before eighteen months for cleft palate.[1] Speech therapy and dental care may also be needed.[1] With appropriate treatment, outcomes are good.[1]
Cleft lip and palate occurs in about 1 to 2 per 1000 births in the developed world.[2] Cleft lip is about twice as common in males as females, while cleft palate without cleft lip is more common in females.[2] In 2017, it resulted in about 3,800 deaths globally, down from 14,600 deaths in 1990.[3][4] The condition is also known as a "hare-lip" because of its resemblance to a hare or rabbit.[5]
Signs and symptoms
Cleft lip
If the cleft does not affect the palate structure of the mouth, it is referred to as cleft lip. Cleft lip is formed in the top of the lip as either a small gap or an indentation in the lip (partial or incomplete cleft), or it continues into the nose (complete cleft). Lip cleft can occur as a one-sided (unilateral) or two-sided (bilateral) condition. It is due to the failure of fusion of the maxillary prominence and medial nasal processes (formation of the primary palate).
The blue lines indicate incisions.
Movement of the flaps; flap A is moved between B and C. C is rotated slightly while B is pushed down.
Pre-operation
Post-operation, the lip is swollen from surgery and will look more natural within weeks. See photos in the section above.
Cleft lip and palate occurs in about 1 to 2 per 1000 births in the developed world.[2]
Rates for cleft lip with or without cleft palate and cleft palate alone varies within different ethnic groups.
According to CDC, the prevalence of cleft palate in the United States is 6.35/10000 births and the prevalence of cleft lip with or without cleft palate is 10.63/10000 births.[82] The highest prevalence rates for cleft lip, either with or without cleft palate are reported for Native Americans and Asians. Africans have the lowest prevalence rates.[83]
Cleft lip and cleft palate caused about 3,800 deaths globally in 2017, down from 14,600 deaths in 1990.[4]
Prevalence of "cleft uvula" has varied from 0.02% to 18.8% with the highest numbers found among Chippewa and Navajo and the lowest generally in Africans.[84][85]
Cleft lip in a Boxer
Cleft lip in a Boxer with premaxillary involvement
Same dog as picture on left, one year later
Cleft lips and palates are occasionally seen in cattle and dogs, and rarely in goats, sheep, cats, horses, pandas and ferrets. Most commonly, the defect involves the lip, rhinarium, and premaxilla. Clefts of the hard and soft palate are sometimes seen with a cleft lip. The cause is usually hereditary. Brachycephalic dogs such as Boxers and Boston Terriers are most commonly affected.[110] An inherited disorder with incomplete penetrance has also been suggested in Shih tzus, Swiss Sheepdogs, Bulldogs, and Pointers.[111] In horses, it is a rare condition usually involving the caudal soft palate.[112] In Charolais cattle, clefts are seen in combination with arthrogryposis, which is inherited as an autosomal recessive trait. It is also inherited as an autosomal recessive trait in Texel sheep. Other contributing factors may include maternal nutritional deficiencies, exposure in utero to viral infections, trauma, drugs, or chemicals, or ingestion of toxins by the mother, such as certain lupines by cattle during the second or third month of gestation.[113] The use of corticosteroids during pregnancy in dogs and the ingestion of Veratrum californicum by pregnant sheep have also been associated with cleft formation.[114]
Difficulty with nursing is the most common problem associated with clefts, but aspiration pneumonia, regurgitation, and malnutrition are often seen with cleft palate and is a common cause of death. Providing nutrition through a feeding tube is often necessary, but corrective surgery in dogs can be done by the age of twelve weeks.[110] For cleft palate, there is a high rate of surgical failure resulting in repeated surgeries.[115] Surgical techniques for cleft palate in dogs include prosthesis, mucosal flaps, and microvascular free flaps.[116] Affected animals should not be bred due to the hereditary nature of this condition.
Notes
Further reading