Cherubism

What is Cherubism?

Cherubism is a congenital childhood disease considered to be of autosomal dominant inheritance. Cherubism is characterized by having painless bilateral enlargement of an individual’s jaws whereby fibrous tissue replaces the bone. ¹

Cherubism is also referred to as familial fibrous dysplasia affecting the jaws although new genetic investigations tend to indicate that it is a separate entity.

This condition is usually diagnosed among children in the age of 2 to 7 years. In these children, there is observation of the symptoms increasing within the first 2 years following diagnosis (between 7 and 9 years), but the symptoms tend to stabilize or regress after puberty. Cherubism affects more boys than girls in a ratio of 2:1.

Beginning the period in early childhood, there is observation of the lower jaw also called mandible and the upper jaw also called maxilla enlarging as the bone begins to be placed with painless growths that look like a cyst.

The growths make the cheeks have a swollen appearance that is round and tends to interfere with the usual development of teeth.

In some people, the disorder may be mild and it might not be noticed, but in others, it is quite severe and highly noticeable with some vision problems or speech, swallowing, and breathing troubles. ³

Causes

Medical researchers believe that cherubism occurs when mutation or changes in a gene that controls the function of cells responsible for building up bone also known as osteoblasts or those cells responsible for breaking down bones also referred to as osteoclasts work in an abnormal way.

In normal circumstances, osteoblasts and osteoclasts work in a balanced way by building up as well as breaking down bones, thus ensuring that the strength of the bone has been maintained.

In individuals having genetic makeup that causes cherubism, their bone breakdown occurs at an increased rate and building it up occurs in an unusual way. The building up of the bone occurs through large multinucleated cells.

It is the imbalanced osteoclast and osteoblast activity, which is thought to contribute to the formation of fibrous tissue. The tissue appears as spongy substance or bubbles in radiographs.

In cherubism observation, the lesions are graded in different levels, which indicate the involvement of bones of the mandibles or maxilla as well as the resorption of teeth’s roots. The grading of the cherubism may also involve the orbits.

Studies on Cherubism

Research done on genetic materials picked from persons coming from families that have multi-generation diagnosis of cherubism has given the conclusion that a number of cherubism cases could be due to mutation changes that occur in the protein SH3BP2. The gene is found on the 4^th chromosome.

A pattern of inheritance has been seen in the groups of multi-generation families diagnosed with the disorder and that pattern suggests that the gene involved is autosomal dominant. So, what does autosomal dominant mean?

This means that an affected parent is able to pass the condition to their offspring or children. On average, about 50 percent of the parents’ children can receive the gene. It has also been discovered that spontaneous cases can occur.

Again, the disorder tends to have varying penetrance, which means that the symptoms may manifest in different forms among the individuals of the same family who carry the said gene.

In the research, scientists have also identified that almost all boys and men having the gene are able to express it meaning they display the symptoms, however, in about 30 to 50 percent of girls and women having the gene don’t express it (they don’t show symptoms). ²

Symptoms

Clinical features of this disorder include:

Swelling of the jaw that occurs bilaterally- meaning on both sides and in same area. However, the swelling may not be occurring with the same degree.
The swelling is common in mandible than it is in maxilla
An individual has upturned eyes where the rim of sclera or the white of a person’s eye tends to be visible beneath the iris
The swelling is painless
There is enlargement of submandibular lymphnodes
The palate arches, which are the curved back portions of a mouth’s roof appear inverted V-shaped
There is premature loss of the primary teeth
There is rapid development of the symptoms in children but this slows down during puberty. The symptoms later on stabilize and may disappear on their own.
The permanent teeth may not erupt or if they do, they may be in random distribution
At times, the disorder could be associated with another condition known as Noonan syndrome in which there are symptoms such as abnormal facial appearance having features such as sunken chest, low set ears, mild low bone density, low platelets, and subtle heart defects.

Diagnosis

Diagnosis of this condition is dependent on the underlying symptoms. Usually a physical examination is conducted by the doctor.

A family history may be looked at to see if people of the same family have experienced the symptoms. In addition to that, imaging tests using panoramic X-rays or CT scans may be ordered to further examine the symptoms.

A doctor may order for biopsies to be conducted to help find out if there is presence of cell patterns that resemble those of cherubism within the lesions.

Treatment

The treatment of cherubism depends on the symptoms. Here are the treatment options a doctor may pursue to help the patient:

Close monitoring of children having cherubism should be done by physicians and dentists. If lesions are occurring within the orbits, then an ophthalmologist should ensure he or she monitors the optic nerve. This way, if there are complications, treatment can be offered accordingly.
Surgery may be done on an individual if they have serious facial appearances that are causing worrisome image problems. The surgery is aimed at removing the fibrous tissue. An important thing to point out here is that since surgery is considered a risky undertaking, and considering that the symptoms may regress or disappear on their own after puberty, it is recommended that an option for surgical treatment be delayed to see if there is spontaneous regression taking place. If that happens, it may mean that there may be no need for surgery.
If a patient has malplaced teeth, he or she may require adjustment through orthodontia. At times, the teeth may be extracted. Malplaced teeth could cause chewing problems and serious image problems, which may in turn cause mental and psychological problems.
If teeth are missing, a replacement with prostheses may be needed

Management

To help patients with this disorder, a doctor may provide disease management tips. First, radiation should never be recommended as a treatment option. To date, there seems to be no any specific established medical or clinical intervention in regard to the growth phase of the disorder.

Because the condition can affect the mental wellness of the child, parents should make sure that they talk about it with their affected children.

The children need to understand the condition and the body and mental changes it may bring in them. This is important especially during the teen age when kids become conscious of their body appearance.

Prevention

Since this disorder is associated with changes in genes, the only way to help reduce its recurrences if by having genetic counseling. Because of lack of severe symptoms among parents, it may be the main cause of failure to recognize the disorder.

It is important to have parents tested for gene mutations before they have children. Again, since this disease arises due to genetic mutation, and considering that the gene may spontaneously mutate, it means that there may be no specific technique to prevent it from occurring.

Complications

An individual with this disorder may have other complications, which may come about due to the underlying symptoms.

For instance, a person with facial appearance being atypical may feel that they are different from the others. This could result in psychological and mental problems and therefore counseling may be needed. Children in their adolescence and teen age may be most affected.

An individual may have difficulties in eating if there is loss of teeth or misplacement of the teeth. When cherubic lesions occur in floor of a person’s orbit, it could affect their sight. There may be an impaired jaw motion when cherubic lesions occur in back part of the mandible.

Reference List

Cherubism: Clinicoradiographic Features and Treatment. http://www.ejomr.org/JOMR/archives/2010/2/e2/e2ht.pdf
About Cherubism. https://www.fibrousdysplasia.org/disease-information/about-cherubism/
Cherubism. https://ghr.nlm.nih.gov/condition/cherubism
https://en.wikipedia.org/wiki/Cherubism