Cleft lip is a complex congenital anomaly that can be either in isolation or seen together with other malformations. It can occur with or without cleft palate. It occurs during the embryonic stage of development. Cleft lip is caused by the failure of maxillary prominence and medial nasal prominence to fuse. This fusion is supposed to happen between the fifth and sixth week of embryonic development.
Normally, the palate develops after the primary palate has been formed between the sixth and seventh week, followed by the formation of the secondary palate at the ninth week of embryonic development. The secondary palate forms the hard and soft palates. Oral clefts have been identified as a common birth defect and it is more common in males.
The oral cleft can either be isolated or due to a genetic syndrome. Isolated clefts are those that occur where there have not been any other clinical findings present. They are due to a combination of a number of factors including genetic and environmental factors. Research shows that approximately 80% of the clefts are isolated.
Prenatal exposure to teratogenic agents like thalidomide, cigarettes, alcohol, anticonvulsants and retinoic acid, maternal diseases like diabetes and rubella and the presence of amniotic bands increase chances of developing oral clefts. The genetic syndromes include Pierre Robin sequence, cytogenic abnormalities like aneuploidies and microdeletions and single-gene disorders like Mendelian.
The chances of an embryo developing an oral cleft can be determined by a thorough medical history, pregnancy history and a dysmorphology exam by a clinical geneticist. It is important for one to undergo this genetic evaluation.