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Paediatric Laboratory Medicine

Simpson-Golabi-Behmel Syndrome: GPC3 Sequencing

Clinical Significance

Simpson-Golabi-Behmel Syndrome (SGBS) is an X-linked overgrowth disorder characterized by pre- and postnatal overgrowth, minor facial anomalies, skeletal/hand anomalies, genitourinary abnormalities and supernumerary nipples. Mental retardation is not constantly found and is usually mild. Patients with SGBS also show an increased risk for development of embryonal tumours, especially Wilms’ tumour.

The main gene identified to cause SGBS is called Glypican 3 (GPC3) and is located at Xq26 on the X chromosome. Glypican 3 appears to play an important role in embryonic growth by regulating cell proliferation and apoptosis. Since males have one X chromosome, if that X chromosome carries the deletion/point mutation in the GPC3 gene, the boy will have SGBS. As a result, males are most often affected. Since females have two X chromosomes, if one X chromosome carries the mutation in the GPC3 gene and the other one does not, the girl will be a carrier of SGBS. Female carriers may have a milder phenotype because of the effect of Lyonization.

Affected males will have carrier daughters since the X chromosome with the deletion/point mutation will be passed from the father to his daughters, and affected males will have unaffected sons, since they will inherit the father’s Y chromosome. If a female is a carrier, her sons have a 50% chance of inheriting the mutation and being affected with SGBS. Her daughters have a 50% chance of inheriting the mutation and being carriers themselves, and may exhibit milder features of SGBS.

Approximately 40% of affected males have a deletion in the GPC3 gene. Point mutations in the GPC3 gene have also been reported.

Test Name

Simpson-Golabi-Behmel Syndrome: GPC3 Sequencing

Alternate Name/ Synonym

  • SGBS

Gene Name

  • GPC3

Test Code



Molecular Genetics



External Proficiency Testing


Turn Around Time

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


Glypican 3


Simpson-Golabi-Behmel Syndrome

Specimen Type

Blood; extracted DNA is not accepted for GPC3 and GPC4 Deletion/Duplication Analysis

If sending a prenatal sample, please contact the laboratory prior to sending sample to discuss sample requirements.

For details about specimen requirements, please refer to: 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)


Room Temperature

Special Requirements

Special Instructions for Genome Diagnostics Samples

If sample shipment >48 hours, ship on ice.

Approval is not required

CPT Codes


Shipping and Contact Information

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


Interpretation is provided in report

Information Sheet: Simpson Golabi Behmel Syndrome