Genotype HLA associated with Coeliac Disease

Clinical information

Diagnostic Utility:

90% of patients with celiac disease have the HLA-DQ2 molecule, a heterodimer formed by the HLA-DQA1*05 and DQB1*02 alleles. This strong association means that determining the DQ2 genotype serves as a diagnostic test when other tests are not conclusive. In the case of DQ8, it is present in 5% of celiacs and its determination is made by detecting the presence of the DQB1*0302 allele. The other 5% of patients with celiac disease have one of the 2 genes that form DQ2, but do not have the complete heterodimer.

Method:

Genotyping of the HLA-DQ2 (alleles DQA1*05/DQB1*02) and DQ8 (allele DQB1*0302) antigens by real-time PCR with FRET hybridization probes.

Reference Values

A result with a Ct (cycle threshold) of less than 35 cycles is considered positive. In the genotyping of the HLA-DQ2 and DQ8 antigens, the possible results are: positive or negative for DQB1*02, positive or negative for DQB1*03:02 (DQ8), and positive or negative for DQA1*05.

It has been observed that depending on the genotype, there is a differential risk range of association with Celiac Disease, from highest to lowest risk: DQ2/DQ2 individuals, DQ2/other, DQ8/other, and finally those who only have one of the 2 alleles that form DQ2.

Diagnostic Algorithm:

Not applicable.

Turnaround Time:

15 working days.

Specimen information

Sample: Whole blood
Tube: 4 ml EDTA K3 tube
Minimum volume: 500µl.

Stability:

• In refrigeration: 2 weeks.
• At -20ºC: from 2 weeks onwards.

Transport instructions: Preferably at room temperature

Reason for rejection: Coagulated sample.

Administrative information

BST Code: LRD2055
Test Description: HLA Genotype associated with Celiac Disease
Synonyms: Not applicable.
Section: Histocompatibility and Immunogenetics
BST Rate: Check the updated rates here.
Profiles: Not applicable.

References

Manual dels "Standards for Histocompatibility Testing" de l'EFI (darrera versió).