Several genes have been associated with craniofacial disorders through experimentation, including sequencing Mendelian clefting syndromes. Over 25 loci have been identified as potential influencers of craniofacial clefts across populations. Linked Genes
The transforming growth factor (TGF) family has provided multiple candidate genes linked with craniofacial development and malformation. TGF is involved in cell migration, differentiation, and proliferation, as well as regulating the extracellular matrix. Another gene that has been flagged as causal for craniofacial disorders, including CL/P, is interferon regulatory factor 6 or, IRF6. Mutations in IRF6 cause Van der Woude syndrome, the most common clefting syndrome. Ventral anterior homeobox 1, VAX1, and noggin, NOG, were identified with genome-wide significance for contributing to CL/P. Additionally, mutations in SPECC1L have recently been identified as influential to facial structure formation, and as causal for syndromic facial clefting. Nonsyndromic CL/P has been associated with the transcription factor forkhead box protein E1 (FOXE1), as mutations have resulted in cases of CL/P in mice. Other genes which have been found to interact with or contribute to craniofacial clefting include FGFRs, TWIST, MSXs, GREM1, TCOF1, PAXs, MAFB, ABCA4, and WNT allowing great cause for more research into the genetic basis for craniofacial disorders. Prevention
Because the cause of facial clefts still is unclear, it is difficult to say what may prevent children being born with facial clefts. It seems that folic acid contributes to lowering the risk of a child being born with a facial cleft.
Like the other clefts, Tessier number 11 is in extent to number 3, number 10 is in extent to number 4 and number 9 is in extent to number 5. Lateral clefts
The lateral clefts are the clefts which are positioned horizontally on the face. These are Tessier number 6, 7 and 8. Tessier number 6 runs from the orbit to the cheek bone. Tessier number 7 is positioned on the line between the corner of the mouth and the ear. A possible lateral cleft comes from the corner of the mouth towards the ear, which gives the impression that the mouth is bigger. It’s also possible that the cleft begins at the ear and runs towards the mouth. Tessier number 8 runs from the outer corner of the eye towards the ear. The combination of a Tessier number 6-7-8 is seen in the Treacher Collins syndrome. Tessier number 7 is more related to hemifacial microsomia and number 8 is more related to Goldenhar syndrome. Van der Meulen classification
Van der Meulen classification divides different types of clefts based on where the development arrest occurs in the embryogenesis. A primary cleft can occur in an early stage of the development of the face (17 mm length of the embryo). The developments arrests can be divided in four different location groups: internasal, nasal, nasalmaxillar and maxillar. The maxillar location can be subdivided in median and lateral clefts. Internasal dysplasia
Internasal dysplasia is caused by a development arrest before the union of the both nasal halves.