HLA genotyping is useful in the evaluation of the risk for coeliac disease in the 1st-degree relatives of patients with coeliac disease

Objective. Coeliac disease (CD) is a common disease with a strong heredity. About 10-20% of 1st-degree relatives of probands develop CD. Relatives should be screened for CD, because if not treated, CD exposes patients to numerous complications. The heterogeneity of symptoms and the lifetime-spanning risk of CD render the timing of CD antibody and/or gastroscopy screenings difficult. As CD susceptibility has been shown to be strongly associated with the HLA alleles DQA1*0501 and DQB1*0201 (together encoding the DQ2 heterodimer) and DRB1*04 (associated with the DQ8 heterodimer), our aim was to investigate whether HLA genotyping might be useful in the identification of 1st-degree relatives of CD patients who do not need further screening for CD. Material and methods. The study comprised 54 Finnish CD families including 54 CD probands and 382 living 1st-degree relatives. All subjects who were willing to participate were screened for CD (duodenal and skin biopsies; endomysial, reticulin and gliadin antibodies). The DQA1*0501, DQB1*0201 and DRB1*04 allele frequencies of CD patients and the 1st-degree relatives were determined. Results. Altogether 17.6% (5.9% of the parents, 15.7% of the siblings, 25.8% of the offspring) of the investigated 1st-degree relatives (n=245) did not carry any of the alleles studied. All of the CD patients (n=136) with the exception of one (0.7%) carried at least one of the alleles investigated. Conclusions. By using the HLA genotyping a considerable proportion of 1st-degree relatives of CD probands could be excluded from further screening for CD.