Cherubism

Excerpt

Clinical characteristics: Cherubism is a childhood-onset, autoinflammatory bone disease characterized by bilateral and symmetric proliferative fibroosseous lesions limited to the mandible and maxilla. The enlargement is usually symmetric in nature. The phenotype ranges from no clinical manifestations to severe mandibular and maxillary overgrowth with respiratory, vision, speech, and swallowing problems. In most affected persons, teeth are displaced, unerupted, unformed, or absent, or may appear to be floating in cystlike spaces; malocclusion, premature exfoliation of deciduous teeth, and root resorption have also been reported. The course and duration of the active process of bone destruction varies between affected individuals; the onset is usually in early childhood, and typically new lesions can occur until puberty. Regression of the lesions occurs as they become filled with bone and remodel during the second and third decade of life. By age 30 years, the facial abnormalities associated with cherubism are not usually recognizable and residual deformity of the jaws is rare. Typically, cherubism is an isolated benign condition; the affected person has normal intellectual skills and is without other physical anomalies.

Diagnosis/testing: Diagnosis is established in a proband with typical clinical, radiographic, and histologic findings and/or a heterozygous pathogenic variant in SH3BP2 identified by molecular genetic testing.

Management: Treatment of manifestations: Given that cherubism is considered to be a self-limited condition that improves over time, treatment should be tailored to the individual's presentation and the evolution of the disease. Ongoing management by a craniofacial team in a major pediatric medical center is recommended; depending on the severity, surgery may be needed for functional and esthetic concerns.

Surveillance: Long-term follow up with clinical, radiographic, dental, orthodontic, and ophthalmologic evaluations. Annual reviews are indicated while new cysts continue to form or established cysts enlarge; after the disorder becomes quiescent, follow up every two to five years.

Testing of relatives at risk: When the pathogenic variant in the family is known, molecular testing can be used to identify mildly affected relatives who may benefit from early intervention; otherwise, clinical and radiographic evaluations can identify relatives at risk.

Genetic counseling: Cherubism is inherited in an autosomal dominant manner. The proportion of cases caused by de novo pathogenic variants is unknown because of variable expressivity and reduced penetrance. Each child of an individual with cherubism has a 50% chance of inheriting the pathogenic variant. Prenatal diagnosis for a pregnancy at increased risk and preimplantation genetic testing are possible if the pathogenic variant has been identified in the family.