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Test Code IL2RG SEQ IL2RG Gene Sequencing

Important Note

Test availability is limited to Seattle Children’s Hospital and University of Washington patients.

Clinical System Name

IL2RG Gene Sequencing

Synonyms

P64; CIDX; IMD4; CD132; SCIDX; IL-2RG; SCIDX1

Description

The protein encoded by this gene is an important signaling component of many interleukin receptors, including those of interleukin -2, -4, -7 and -21, and is thus referred to as the common gamma chain. Mutations in this gene cause X-linked severe combined immunodeficiency (XSCID), as well as X-linked combined immunodeficiency (XCID), a less severe immunodeficiency disorder.

Sample Requirements

Specimen: Whole blood

Container(s): Dark Green/Sodium Heparin, Lavender/EDTA

Preferred Vol: 5 mL

Minimum Vol: 3 mL

 

Specimen: Extracted DNA

Minimum: 5µg

Note: DNA concentration minimum 100 µg/mL; 260/280 ratio 1.70-2.00

  

Specimen: Cultured cells

Acceptable:  Fibroblasts, amniocytes, chorionic villus sampling (CVS)

Container(s): T-25 flasks

Preferred Vol: 2 flasks

 

Note: Direct testing on amniocentesis and chorionic villus sampling (CVS) is not performed; samples must be cultured by external lab.

Processing Instructions

Reject due to: Clotting

Spin: No

Aliquot: No

Temp: Room temperature

Storage location: Molecular Genetics box in CPA Refrigerator #2

 

Off-site collection: Refrigerate blood samples until ready to ship. Transport all sample types at room temperature via overnight shipping

Stability

 

Specimen Type Temperature Time
Cultured cells Room temp 3 days
Whole blood, extracted DNA Room temp 3-5 days
Whole blood, extracted DNA Refrigerated 7 days
Extracted DNA Frozen 5 years

 

Note: Whole blood samples > 7days may be submitted to be assessed by our lab for acceptability for testing.

Availability

STAT Performed TAT
Contact lab Monday - Friday 8-10 weeks

 

Performing Laboratory

Seattle Children's Laboratory

Department

Department:  Molecular Genetics Lab

 

Lab Client Services: 206-987-2617, labclientservices@seattlechildrens.org

Lab Genetic Counselor: LabGC@seattlechildrens.org

Reference Range

Interpretive report will be provided

Methodology

Method: The 8 exons of the IL2RG gene, including exon/intron boundaries, will be amplified from genomic DNA by PCR and sequenced bidirectionally using dye-terminator chemistry.

 

 

Limitations: Mutations in the promoter region, large deletions, large duplications, or rare recombinant mutations may not be detected by this method.

CPT Codes

81405

Special Instructions

Links to:  Immunology Diagnostic Laboratory

Requisition

IDL Requisition

Clinical Utility

To determine if there is occurrence of variation in patient IL2RG sequence compared to wild type.