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Test Code XIAP Seq XIAP (BIRC4) Gene Sequencing

Important Note

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

Clinical System Name

XIAP (BIRC4) Gene Sequencing

Synonyms

API3; ILP1; MIHA; XLP2; BIRC4; IAP-3; hIAP3; hIAP-3

Description

This gene encodes a protein that belongs to a family of apoptotic suppressor proteins. Mutations in this gene are the cause of X-linked lymphoproliferative syndrome. Approximately 20% of patients with missense mutations in XIAP (BIRC4) may however have normal XIAP protein expression.  Therefore, if clinical suspicion for XLP2 remains high, sequencing of XIAP (BIRC4) gene is recommended.

 

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 temp 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 Laboratory

 

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 6 exons of the XIAP (BIRC4) 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

81479

Special Instructions

Links to:  Immunology Diagnostic Laboratory