HLA-DQA1 and HLA-DQB1 in Celiac disease predisposition: Practical implications of the HLA molecular typing

Celiac disease (cd) is a multifactorial disorder with an estimated prevalence in europe and usa of 1:100 and a female:male ratio of approximately 2:1. the disorder has a multifactorial etiology in which the triggering environmental factor,the gluten,and the main genetic factors,human leukocyte antigen (hla)-dqa1 and hla-dqb1 loci,are well known. about 90-95% of cd patients carry dq2.5 heterodimers,encoded by dqa1*05 and dqb1*02 alleles both in cis or in trans configuration,and dq8 molecules,encoded by dqb1*03:02 generally in combination with dqa1*03 variant. less frequently,cd occurs in individuals positive for the dq2.x heterodimers (dqa1*05 and dqb1*02) and very rarely in patients negative for these dq predisposing markers. hla molecular typing for celiac disease is,therefore,a genetic test with a negative predictive value. nevertheless,it is an important tool able to discriminate individuals genetically susceptible to cd,especially in at-risk groups such as first-degree relatives (parents,siblings and offspring) of patients and in presence of autoimmune conditions (type 1 diabetes,thyroiditis,multiple sclerosis) or specific genetic disorders (down,turner or williams syndromes). © 2012 megiorni and pizzuti; licensee biomed central ltd.