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Paediatric Laboratory Medicine

Cherubism: SH3BP2 Sequencing

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.

Test Name

Cherubism: SH3BP2 Sequencing

Alternate Name/ Synonym

  • Familial fibrous dysplasia of the jaw

Gene Name

  • SH3BP2

Alternate Gene Name

CRBM

Test Code

CHERU

Division

Molecular Genetics

Method

Sequencing

External Proficiency Testing

CAP

Turn Around Time

2 weeks (Prenatal samples), 2-3 weeks (Pregnancy/Urgent samples), 4-6 weeks (Routine)

Protein

SH3 domain-binding protein 2

Disease/Condition

Cherubism

Specimen Type

Blood; gDNA.

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

Minimum Specimen Requirements

5-10 mL EDTA or ACD 0.5 mL EDTA (neonate); minimum 10 ug in 100 uL low TE (pH8.0)

Storage/Transportation

Room Temperature

Special Requirements

Special Instructions for Genome Diagnostics Samples

If sample shipment >48 hours, ship on ice.

Approval is not required

CPT Codes

81479

Shipping and Contact Information

The Hospital for Sick Children
Rapid Response Laboratory
170 Elizabeth Street, Room 3642
Toronto, ON
M5G 2G3
Canada
Phone: 416-813-7200
Phone: 1-855-381-3212

Interpretation

Interpretation is provided in report

Information Sheet: Cherubism