Cherubism: SH3BP2

Alternate test name

Familial fibrous dysplasia of the jaw

Gene name / Alternate gene name

SH3BP2

CRBM

Protein

SH3 domain-binding protein 2

Lab area

Genome Diagnostics - Molecular Genetics

Method and equipment

Targeted analysis of recurrent mutations in exon 9; Sequencing of the coding and flanking regions of the entire SH3BP2 gene

Expected turn-around time

Prenatal samples: 2 weeks Pregnancy/STAT: 2-3 weeks Routine: 4-6 weeks

Specimen type

Blood; gDNA.

For details about specimen requirements, please refer to the pdf: Specimen Type & Requirements (PDF).

Specimen requirements

Blood: 5-10 mL in EDTA, 0.5 mL in EDTA (neonate);
DNA-minimum 10 ug in 100 uL low TE (pH8.0)

Storage and transportation

Room Temperature

For details about specimen requirements, please refer to: Specimen Type and Requirements

Special requirements

Special Instructions for Genome Diagnostics Samples

If sample shipment >48 hours, ship on ice.

Shipping information

The Hospital for Sick Children

Division of Genome Diagnostics

555 University Avenue, Black Wing, Room 3416

Toronto, ON

Canada

M5G 1X8

Phone: 416-813-7200 ext. 2

Hours: Monday to Friday, 8 a.m. to 4:30 p.m.

Off hours: Please send to Rapid Response Laboratory, 555 University Avenue, Room 3642

Email Molecular Lab: molecular.lab@sickkids.ca

Email Cytogenetics: cytogenetics.requests@sickkids.ca

Requisition

Cherubism: SH3BP2 - requisition

Background and clinical significance

Cherubism is a rare autosomal dominant condition of the mandible and maxilla. It causes round cheeks and jaws with slight upward turning of the eyes giving a facial appearance reminiscent of the angelic cherubs. The basis for the fullness of cheeks and jaws is a non-neoplastic fibrous dysplasia within the maxilla and mandible. Both ends of the spectrum, mild clinically unrecognized cases, and severe cases with extensive bone loss are seen. In some severe cases, the marked deformation results in chewing, speech, and swallowing difficulties and in rare cases, severe orbital involvement leading to diplopia may occur. Patients with Cherubism may show variability in clinical features due to incomplete penetrance and variable expressivity. In males the penetrance is close to 100% but in females only 50-75%.

The gene for Cherubism is SH3BP2, which has been localized to chromosome 4p16.3. Eleven different missense mutations for Cherubism have been described so far, all of them have been found in exon 9 of the SH3BP2 gene.

Cherubism is present when an individual has one copy of the defective gene. Affected individuals have a 50% chance of transmitting the disorder to each child. There is a 50% chance that the affected individual’s offspring will not be affected with Cherubism.

See related information sheet: Cherubism

Disease condition

Cherubism