Most males have mild symptoms such as hypertelorism and a broad nasal base with bifid nose, but can also be a carrier of the mutation yet stay clinically unaffected. Genetics
CFND is a very rare X-linked malformation syndrome caused by mutations in the ephrin-B1 gene (EFNB1). The EFNB1 gene codes for a membrane-anchored ligand which can bind to an ephrin tyrosine-kinase receptor. This ephrin receptor is, amongst other things, responsible for the regulation of embryonic tissue-border formation, and is important for skeletal and craniofacial development. As the ephrin receptor and its EFNB1 ligand are both bound to the (trans)membrane of the cell its cascade is activated through cell-cell interactions. These cell-cell interactions are disturbed due to the presence of cells with the mutant EFNB1 gene, as a result causing incomplete tissue-border formation.Paradoxical to other X-linked conditions, with CFND the females are more severely affected than males. This is due to the process of X-inactivation in females, where at random either the maternal or paternal X-chromosome is inactivated in a cell. Due to this process, the body’s tissues contain either cells with normal EFNB1 or the mutated EFNB1. This is called a mosaic pattern. This mosaic pattern of cells interferes with the functionality of the cell-cell interactions, as a result causing the severe physical malformations in females.As with all X-linked conditions CFND has a preset chance of being passed down from parents to their offspring. Females have two X-chromosomes and males have one X-chromosome.
A torus palatinus (pl. tori palatini), or palatal torus (pl. palatal tori), is a bony protrusion on the palate. Palatal tori are usually present on the midline of the hard palate. Most palatal tori are less than 2 cm in diameter, but their size can change throughout life. Types
Sometimes, the tori are categorized by their appearance. Arising as a broad base and a smooth surface, flat tori are located on the midline of the palate and extend symmetrically to either side. Spindle tori have a ridge located at their midline. Nodular tori have multiple bony growths that each have their own base. Lobular tori have multiple bony growths with a common base. Cause
Although some research suggest palatal tori to be an autosomal dominant trait, it is generally believed that palatal tori are caused by several factors. They are more common in early adult life and can increase in size. In some older people, the size of the tori may decrease due to bone resorption. It is believed that tori of the lower jaw are the result of local stresses and not due solely to genetic influences. Treatment
Palatal tori are usually a clinical finding with no treatment necessary. It is possible for ulcers to form on the area of the tori due to repeated trauma. Also, the tori may complicate the fabrication of dentures. If removal of the tori is needed, surgery can be done to reduce the amount of bone present. Surgical removal
A maxillary torus is only removed in instances where it is problematic.