The biologic mechanisms of mutual recognition of the two cabinets, and the way they are glued together, are quite complex and obscure despite intensive scientific research.Orofacial clefts may be associated with a syndrome (syndromic) or may not be associated with a syndrome (nonsyndromic). Syndromic clefts are part of syndromes that are caused by a variety of factors such as environment and genetics or an unknown cause. Nonsyndromic clefts, which are not as common as syndromic clefts, also have a genetic cause. Genetics
Genetic factors contributing to cleft lip and cleft palate formation have been identified for some syndromic cases. Many clefts run in families, even though in some cases there does not seem to be an identifiable syndrome present. A number of genes are involved including cleft lip and palate transmembrane protein 1 and GAD1, One study found an association between mutations in the HYAL2 gene and cleft lip and cleft palate formation. Syndromes
The Van der Woude syndrome is caused by a specific variation in the gene IRF6 that increases the occurrence of these deformities threefold. Mutations in interferon regulatory factor 6 (IRF6) that cause cleft lip palate are also implicated in neural tube defects such as spina bifida. Another syndrome, Siderius X-linked intellectual disability, is caused by mutations in the PHF8 gene (OMIM: 300263); in addition to cleft lip or palate, symptoms include facial dysmorphism and mild intellectual disability.In some cases, cleft palate is caused by syndromes that also cause other problems:

Stickler syndrome can cause cleft lip and palate, joint pain, and myopia.
Craniodiaphyseal dysplasia (CDD), also known as lionitis, is an extremely rare autosomal recessive bone disorder that causes calcium to build up in the skull, disfiguring the facial features and reducing life expectancy. These calcium deposits decrease the size of cranial foramina, and can decrease the circumference of the cervical spinal canal. In the few cases recorded, most died in childhood. Cause
The underlying genetics are uncertain. Diagnosis
Among the medical signs are dacryocystitis, seizures, intellectual disability, and paralysis, each of which is a complication resulting from the diminutive foramina. A common sign reported as a result of the disease has been widely spaced eyes. Society
Peter Bogdanovichs 1985 drama film Mask drew public attention to the case of Roy L. "Rocky" Dennis, an American boy who died of the disorder in 1978.In the American medical drama Greys Anatomy episode "Yesterday", Jesse Plemons plays a teenage boy with lionitis. The main character of the two-issue comic book miniseries Friday the 13th: How I Spent My Summer Vacation by Wildstorm Productions is a 13-year-old boy with the disorder. In the anthology television series American Horror Story season 1, Beauregard, the brother of Tate and Adelaide, had lionitis. See also
Leontiasis ossea

References
External links
Craniodiaphyseal dysplasia at orpha.net