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Test Code CD40L SEQ CD40L Gene Sequencing

Important Note

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

Clinical System Name

CD40L Gene Sequencing


CD40L; CD40 ligand; IGM; IMD3; TRAP; gp39; CD154; CD40LG; HIGM1; T-BAM; TNFSF5; hCD40L


This gene encodes a protein expressed on T cells that regulates B cell function by interacting with CD40 on the surface of B cells. This interaction initiates immunoglobulin class switching. Defects in CD40L cause the inability for immunoglobulin class switching. CD40L deficiency is associated with hyper-IgM syndrome.

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

Container(s): T-25 flasks

Preferred Vol: 2 flasks

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



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 ok


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


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


Performing Laboratory

Seattle Children's Laboratory


Department: Molecular Genetics Laboratory


Lab Client Services: 206-987-2617,

Lab Genetic Counselor:

Reference Range

Interpretive report will be provided


Method: The 5 exons of the CD40L gene, including exon/intron boundaries, were 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


Clinical Utility

Determine if there is occurrence of variation in patient CD40L sequence compared to wild type.