Background: A cost-effective identification of HLA- DQ risk haplotypes using the single nucleotide polymorphism (SNP) technique has recently been applied in the diagnosis of celiac disease (CD) in four European populations. The objective of the study was to map risk HLA- DQ haplotypes in a group of Danish CD patients using the SNP technique.
Methods: Cohort A: Among 65 patients with gastrointestinal symptoms we compared the HLA- DQ2 and HLA- DQ8 risk haplotypes obtained by the SNP technique (method 1) with results based on a sequence specific primer amplification technique (method 2) and a technique used in an assay from BioDiagene (method 3). Cohort B: 128 patients with histologically verified CD were tested for CD risk haplotypes (method 1). Patients with negative results were further tested for sub-haplotypes of HLA- DQ2 (methods 2 and 3).
Results: Cohort A: The three applied methods provided the same HLA- DQ2 and HLA- DQ8 results among 61 patients. Four patients were negative for the HLA- DQ2 and HLA- DQ8 haplotypes (method 1) but were positive for the HLA- DQ2.5-trans and HLA- DQ2.2 haplotypes (methods 2 and 3). Cohort B: A total of 120 patients were positive for the HLA- DQ2.5-cis and HLA- DQ8 haplotypes (method 1). The remaining seven patients were positive for HLA- DQ2.5-trans or HLA- DQ2.2 haplotypes (methods 2 and 3). One patient was negative with all three HLA methods.
Conclusions: The HLA- DQ risk haplotypes were detected in 93.8% of the CD patients using the SNP technique (method 1). The sensitivity increased to 99.2% by combining methods 1 - 3.
Keywords: Genetic testing; HLA antigens; haplotypes; polymorphism single nucleotide; real-time polymerase chain reaction.