Clefts of the lip and palate represent a heterogeneous group of disorders affecting the lips and oral cavity. The effects on an individual's speech, hearing, appearance and psychology can lead to long-lasting adverse outcomes for health and social integration. Even when repaired, residual problems often remain.
Care requires a multidisciplinary approach from birth to adulthood, involving a range of disciplines, for example plastic surgery, speech and language therapy and counselling.
Prevalence and aetiology
Orofacial clefts are generally divided into isolated cleft palate (CP) and cleft lip with/without cleft palate (CL(P)). Orofacial clefts occur in approximately one in 700 live births, with prevalence varying according to geography and ethnicity.
The highest recorded rates of CL(P) come from Asia and parts of Latin America; the lowest in Africa and southern Europe. CP rates are highest in Finland, Scotland and Canada, and lowest in Africa and parts of Latin America.
There are also gender differences: CL(P) is more frequent in males and CP most typical in females. This seems to be consistent across geographic and ethnic groups. There is also a variation in the gender ratio with severity of the cleft, number of affected siblings in a family, presence of additional malformations and possibly paternal age.
Both types of cleft are frequently associated with other congenital anomalies, although the proportion of individuals with additional anomalies varies greatly between studies.
The aetiology of orofacial clefts is complex but involves both genetic and environmental factors and undoubtedly an interaction between these.
The risk to siblings is greater than that predicted by familial aggregation of environmental risk factors,1 and concordance rates for non-syndromic clefts are higher in monozygotic twin pairs than in dizygotic twins.
Genetic linkage studies have implicated various loci in the cause of clefts. Some loci appear more plausible than others and a number of genes that have causal associations with Mendelian inherited syndromes are strongly linked to the isolated forms - CL and CP.
Inevitably gene-environment interactions could potentially contribute to the aetiology, although many studies investigating such interactions have been inconclusive.
Research has, however, implicated factors such as maternal exposure to tobacco smoke, alcohol, medicines and illicit drugs, viral infection and teratogens in the workplace, as well as nutritional deficiencies in the aetiology of orofacial clefts.
This is reinforced by the finding that pregnancy planning and certain nutritional supplements can offer protection. One study found maternal multivitamin supplement use in early pregnancy was associated with a 25 per cent decreased risk of orofacial clefts.2 The role of folic acid, however, remains uncertain in human cleft lip and palate.
The most consistent factor is maternal smoking, which appears to be linked to both CP and CL(P), with a population attributable risk of 20 per cent.3
The important point to note is that manipulation of the environment is a potential route towards prevention. In addition, the advent of whole genome sequencing, particularly in individuals identified as high risk, offers an opportunity for more specific genetic and lifestyle counselling.
Baby with severe cleft lip and palate
A member of the cleft lip and palate team should see the child and parents as soon as possible after birth to assess the child, provide support and outline future management. A specified member of the team should also provide advice and support on feeding and counselling.
This critical and pivotal role is often filled by a cleft nurse specialist. With appropriate feeding advice, the majority of babies can be successfully breastfed or fed with a nursing bottle and special teat.
The timing of surgery in cleft deformity is a matter of some debate and represents a compromise between function, development and appearance on one hand versus scarring and growth retardation on the other.
Primary surgery for repair of CL is normally carried out at around three months of age with a view to an anatomical repair of the muscles of the lip-nose complex. In cases where the cleft is particularly wide the initial surgery may not achieve complete muscular reconstruction and a revision of the procedure may be required for optimum function and aesthetics.
CP repair aims not only to restore the partition between the oral and nasal cavities, but also to reconstruct the muscular sling of the soft palate. This operation is normally carried out at six to nine months of age, but some surgical teams opt to delay closure of the hard palate in the belief that this will result in better maxillary growth while still enabling reasonably good speech outcomes.
However, some impairment to maxillary growth is inevitable and this may require maxillary surgery in the late teens or early adulthood.
If the cleft involves not only the lip but also the maxillary bone adjacent to the cleft (the alveolus) a further operation is required at around eight to 10 years of age. This procedure often uses bone from the iliac crest and is usually carried out in conjunction with orthodontic treatment for correction of any tooth irregularity and/or expansion of the maxillary arch.
When the growth of both jaws is completed in the late teens, up to 50 per cent of cleft lip and palate patients have a deficiency in maxillary growth to the extent that orthognathic surgery to bring the maxilla forward to a more suitable position is recommended.
- Professor Mossey is a professor of craniofacial development at University of Dundee
1. Wyszynski DF, Zeiger J, Tilli MT et al. Survey of genetic counselors and clinical geneticists regarding recurrence risks for families with nonsyndromic cleft lip with or without cleft palate. Am J Med Genet 1998; 79: 184-90.
2. Johnson CY, Little J. Folate intake, markers of folate status and oral clefts: is the evidence converging? Int J Epidemiol 2008; 37: 1041-58.
3. Little J, Cardy A, Munger RG. Tobacco smoking and oral clefts. Bull World Health Organ 2004; 82: 213-18.