Table of Contents
Introduction
Cherubism will affect the shape of the child’s face. It is a genetic disorder, non-cancerous, and painless growths form in the child’s jaw that leads to a widened jaw and round cheeks. There can be missing or abnormally developed teeth in some children or other signs like eyes that seem to gaze upward. By adult childhood, most cases go away on their own.
What Is Cherubism?
Cherubism is an autoinflammatory condition affecting the bones, especially the jaw and the orofacial cavity, with childhood onset. This disease is primarily characterized by bilateral and symmetric fibro-osseous proliferative lesions and is only limited to the mandible and maxilla of the face. Cherubism was initially described as a "familial multilocular cystic disease of the jaw bone" by Jones in 1933.
What Causes Cherubism?
Most cases of cherubism are due to mutations to the SH3BP2 gene. This gene tells the body how to make the SH3BP2 protein, which plays a role in replacing old bone tissue with new bone, known as bone remodeling. The mutation causes the body to make too much of the SH3BP2 protein.
There will be inflammation of the jaw bone and increased production of osteoclasts due to too much protein. Osteoclasts will break down the tissue when the body does not need it anymore. However, in excess, osteoclasts will start breaking down the bone tissue in the jaw when they are not supposed to. There are cysts-like growths that develop in the jaw due to abnormal bone loss along with inflammation from excessive SH3BP2 protein. This will gradually grow bigger and cause typical features of Cherubism.
What Is the Phenotype of Cherubism?
The phenotype of this disease may range from no clinical manifestations to severe mandibular or maxillary overgrowth that interferes with respiration, speech, and even vision. The affected patient also suffers from dysphagia or difficulty in swallowing. In most affected individuals, either the teeth are displaced or may even remain unerupted, malformed, or absent, which is a very common finding. According to case reports, some individuals’ teeth also appear to float in cystlike spaces or may suffer from severe malocclusion or an incorrect bite. Additional dental clinical features of this pathology are premature exfoliation of the primary or deciduous teeth alongside root resorption.
Although the course and duration of the active disease may vary in the affected individuals, the degree of bone destruction depends on the extent of the lesions. The disease onset is, as per research, in early childhood, wherein typically new lesions manifest till puberty. Regression of these lesions is possible when they become filled with bone and remodel the jaw portion, especially during the second or third decade of life. By the age of 30, though facial abnormalities associated with cherubism are not usually detectable, the childhood condition leaves behind a clinically observable residual deformity of the jaw.
What Are the Inheritance Patterns and Genetic Aspects of Cherubism?
Dental and medical literature implicates that cherubism is, in fact, an isolated condition with a benign nature. Also, the affected person does not suffer from any lack of intellectual skills and can be found to have no physical deformities in other body parts. Cherubism is hypothesized to be inherited in an autosomal dominant manner. The proportion of cherubism cases caused by pathogenic variants is elusive owing to the variability of the disease pattern and genetic pertinence. Each child of an individual who suffers from cherubism may have a 50 % chance of inheriting this pathogenic variant, pertaining to the nature of inheritance. Prenatal diagnosis is essential during pregnancy when there is a family history or known parent with cherubism, and prenatal genetic testing would be advised to detect possible pathogenic variants. When the pathogenic variant can be identified in a family member, then molecular testing can be further ordered to study the genetic or transmission patterns through mildly affected relatives or parents. Prenatal diagnosis of cherubism may hence benefit from early intervention and diagnosis. The same can be achieved through clinical and radiographic evaluations to identify the individuals affected by cherubism or those associated with risk factors.
How Does Cherubism Progress?
The onset of the condition occurs mainly, in most cases, between the ages of two and seven years when a bilateral symmetric enlargement is observed in the mandible (lower jaw) or the maxilla (upper jaw) involving the coronoid region as well but without the involvement of the mandibular condyles. The other craniofacial structures and cranial bones usually remain unaffected. During the initial onset of cherubism, swelling of both submandibular and cervical lymph nodes will be observed. These lesions show a slow progression that speeds up and enlarges by adolescence. Spontaneous regression typically takes place only after puberty and extends well into the late second decade or the early years of the third decade. Patients may also report, in severe cases of cherubism, upturned or tilted eyeballs, missing second and third molars (congenital cases), premature exfoliation of the milk teeth, displacement of permanent teeth because of secondary or enlarged jaw lesions, severe malocclusion causing oral discomfort, etc.
What Are the Diagnostic Studies Done for Cherubism?
1. Radiographic Imaging Studies
Radiographic examinations typically show a bilateral multilocular radiolucency of the affected area within the maxillary or mandibular regions. The coronoid processes may be commonly involved, whereas the condyles are rarely affected. Bony expansile remodeling and thinning of the bone cortex with a characteristic coarse trabecular pattern may also occur, all of which confirm cherubism lesions.
2. Histopathological Diagnosis
Histologic evaluation of lesions, present either in the mandible or maxilla, show non-neoplastic characteristics of fibrotic nature with multiple giant cell formations and cysts along with an increase in the osteoid matrix.
How to Manage Cherubism?
Cherubism is considered a self-limiting condition that eventually improves over time despite severe deforming manifestations. Treatment, however, should be tailored to suit the individual’s clinical presentation and esthetics. These individuals may need physical and social encouragement, and surgery may be needed to improve the person's functional and esthetic features and concerns. Surgical intervention may be done by a maxillofacial surgeon who may curettage the lesion and place a bone graft if needed. The physician or dermatologist may advise liposuction to recontour the disfigured cheeks after surgically treating the affected mandible or maxilla.
Conclusion
To conclude, cherubism is a locally aggressive yet self-limiting condition that may require multidisciplinary intervention comprising a craniofacial specialist, dentist, orthodontist, ophthalmologist (eye specialist), and maxillofacial surgeon. A psychologist can also be of great help to these affected individuals to overcome the potential stress, stigma, and psychological trauma experienced by them. Affected parents can seek help from a genetic counselor before planning their pregnancy.
