Awareness

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 continues into the nose (complete cleft). Lip cleft can occur as one sided (unilateral) or two sided (bilateral). It is due to the failure of fusion of the maxillary and medial nasal processes (formation of the primary palate).

A mild form of a cleft lip is a microform cleft. A microform cleft can appear as small as a little dent in the red part of the lip or look like a scar from the lip up to the nostril. In some cases muscle tissue in the lip underneath the scar is affected and might require reconstructive surgery. It is advised to have newborn infants with a microform cleft checked with a craniofacial team as soon as possible to determine the severeness of the cleft.

Cleft Palate

Cleft palate is a condition in which the two plates of the skull that form the hard palate (roof of the mouth) are not completely joined. The soft palate is in these cases cleft as well. In most cases, cleft lip is also present. Cleft palate occurs in about one in 700 live births worldwide. Palate cleft can occur as complete (soft and hard palate, possibly including a gap in the jaw) or incomplete (a ‘hole’ in the roof of the mouth, usually as a cleft soft palate). When cleft palate occurs, the uvula is usually split. It occurs due to the failure of fusion of the lateral palatine processes, the nasal septum, and/or the median palatine processes (formation of the secondary palate).

The hole in the roof of the mouth caused by a cleft connects the mouth directly to the nasal cavity. (Note: the next image shows the roof of the mouth. For clarity the image depics a toothless infant.)

A direct result of an open connection between the oral cavity and nasal cavity is velopharyngeal insuffficiency (VPI). Because of the gap, air leaks into the nasal cavity resulting in a hypernasal voice resonance and nasal emissions. Secondary effects of VPI include: speech articulation errors (e.g., distortions, substitutions, and omissions) and compensatory misarticulations (e.g., glottal stops and posterior nasal fricatives). Possible treatment options include speech therapy, prosthetics, augmentation of the posterior pharyngeal wall, lengthening of the palate, and surgical procedures.

Causes of Cleft

During the first six to eight weeks of pregnancy, the shape of the embryo’s head is formed. Five primitive tissue lobes grow:

a) one from the top of the head down towards the future upper lip.
b-c) two from the cheeks, which meet the first lobe to form the upper lip.
d-e) and just below, two additional lobes grow from each side, which form the chin and lower lip.

If these tissues fail to meet, a gap appears where the tissues should have joined (fused). This may happen in any single joining site, or simultaneously in several or all of them.

The upper lip is formed earlier than the palate, from the first three lobes named a to c above. Formation of the palate is the last step in joining the five embryonic facial lobes, and involves the back portions of the lobes b and c. These back portions are called palatal shelves, which grow towards each other until they fuse in the middle. This process is very vulnerable to multiple toxic substances, environmental pollutants, and nutritional imbalance. The biologic mechanisms of mutual recognition of the two shelves, and the way they are glued together, are quite complex and obscure despite intensive scientific research.

The cause of cleft lip and cleft palate formation can be genetic in nature. A specific gene may increase the occurrence, although, environmental influences may also cause, or interact with genetics to produce, orofacial clefting. Scientists have investigated seasonal causes (such as pesticide exposure); maternal diet and vitamin intake; retinoids- which are members of the vitamin A family; anticonvulsant drugs; alcohol; cigarette use; nitrate compounds; organic solvents; parental exposure to lead; and illegal drugs as teratogens increase the possibility of clefting. If a person is born with a cleft, the chances of that person having a child with a cleft, given no other obvious factor, rises to 1 in 14. Research continues to investigate the extent to which Folic acid can reduce the incidence of clefting.