Cherubism is genetic disorder of childhood. It is characterized by abnormal bone tissue in the lower part of the face.
Cherubism is due to a problem in bone composition that is largely limited to the upper and lower jaws with loss of bone in the jaws and its replacement by excessive amounts of fibrous tissue. These abnormalities often resolve after puberty. Cherubism is inherited as an autosomal dominant condition. Most boys and girls with it have a parent who had cherubism, while the few children with cherubism without a family history are thought to have a new mutation for cherubism but can transmit it to their children.
Mutations in the SH3BP2 gene cause cherubism. Mutations in the SH3BP2 gene have been identified in about 80 percent of people with cherubism. The SH3BP2 gene provides command for making a protein whose exact function is unclear. The protein plays a role in transmitting chemical signals within cells, particularly cells involved in the replacement of old bone tissue with new bone (bone remodeling) and certain immune system cells. This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.
The overactive protein likely causes irritation in the jaw bones and triggers the production of osteoclasts, which are cells that break down bone tissue during bone remodeling. An excess of these bone-eating cells contributes to the destruction of bone in the upper and lower jaws. Treatment of cherubism included surgery as needed between ages five to 15 years for disfiguring enlargement of jaws or locally aggressive lesions. Other treatment ophthalmologic for displacement of the globe or vision loss. Early orthodontia and/or jaw reconstruction may reduce risk for upper airway obstruction, obstructive sleep apnea, tooth displacement.
