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11. Cleft Lip and Palate
- Hong Kong University Press, HKU
- Chapter
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11 Cleft Lip and Palate Introduction Cleft lip and palate is a congenital malformation of the oral-facial region. Clefts are caused by the failure of certain structures to fuse (unite) in the developing embryo during pregnancy. Clefts of the lip are caused by failure of the fronto-nasal process and the lateral maxillary process to fuse. In the normally developing fetus, this should happen approximately six weeks after conception. Isolated cleft palates are due to the failure of the palatal shelves to join. This occurs in the normal embryo around the eighth or ninth week. Etiology The cause of cleft is not clear and, in individual cases, often cannot be determined. Both hereditary and environmental factors have been identified. The incidence of cleft is higher when another family member also has a cleft, indicating a genetic component. The nature of genetic transmission is not clear, but is probably recessive. Not all cleft cases can be explained on a hereditary basis. Several environmental factors have been identified as possible contributing factors in clefts: • drugs (e.g., cortisone) • infections • diseases 124 Commuication Disorders • metabolic disturbances • environmental pollutants • malnutrition • foetal anoxia • injuries There is speculation that the use of a number of agents during pregnancy may increase the risk of clefts as well as other anomalies. These include: • alcohol • aspirin • caffeine • tobacco When a baby is born with a cleft, most parents feel that it is their fault, that they have caused the cleft by something they have done or not done. This is rarely true. Parents should receive counselling as soon as possible after the birth addressing the following issues: • the etiology of clefts is basically not known • in all likelihood, parents did not cause the cleft by something they did or did not do Classification There are many different classification systems for cleft lip and palate. At a minimium, we need the following information when describing a cleft patient: • laterality (unilateral or bilateral) • location (lip, alveolar ridge, hard palate and/or velum) • extent (complete or incomplete) For example, one patient may have a complete bilateral cleft of the lip; a second an incomplete unilateral (left) cleft lip and alveolus; a third a complete cleft of the hard and soft palate. Incidence The incidence of cleft lip and palate is approximately one in every 750 live births (McWilliams et aI., 1984). There are racial differences in the incidence of cleft lip or palate: Orientals and American Indians have the highest occurrence rate (for Japanese, an estimated 2.13 per 1000) and Blacks have the lowest incidence (1 in 900 to 1 in 3000). One study conducted in Beijing showed an incidence [3.144.212.145] Project MUSE (2024-04-18 00:31 GMT) Cleft Lip and Palate 125 rate of 1.25 and 1.38 per thousand lives births for cleft lip and cleft palate respectively (Liu, 1978). There are an estimated 1 million people in China with cleft lip or palate. There are also sex differences in the frequency of clefts. Clefts involving the lip (with or without cleft palate) occur roughly twice as often among males as females. For isolated cleft palate (that is, no cleft lip), the reverse is true (the incidence is higher for females) . Associated problems A child born with a cleft of the lip and/or palate may have additional problems. Congenital defects There is a higher incidence of congenital defects among children born with clefts than the general population. This incidence is highest among those with clefts of the palate. Examples of accompanying birth defects include congenital heart conditions, club foot, renal anomalies, mental retardation, gastrointestinal defects and microcephaly. There are over 150 syndromes which may include a cleft as one of the symptoms. These include Apert syndrome (acrocephalosyndactyly), Crouzon disease (craniofacial dystonia), Pierre Robin syndrome, and craniofacial microsomia. When a cleft lip or palate is noted at birth, it is important to assess the child thoroughly for other congenital defects. Such defects may be much more serious than the cleft, require urgent medical attention, and influence management of the cleft. For example, if the child has a congenital heart defect, early surgery for the cleft may not be advised. Other problems Children born with a cleft lip or palate may have or develop additional problems which are directly or indirectly related to the cleft. These include: • dental problems • feeding difficulties • psychosocial problems • hearing problems • language problems • speech problems 1. Dental problems. The patient with cleft lip and palate is very likely to have...