title: Limited role of HLA DQ2/8 genotyping in diagnosing coeliac disease.
abstract: The European guidelines for diagnosing coeliac disease in children were revised in 2012. These recommend that in symptomatic children, a diagnosis of coeliac disease can be made without small-bowel biopsies provided their anti-tissue transglutaminase (anti-tTG) titre is >10 times of upper-limit-of-normal (>10×ULN) and anti-endomysial antibody is positive. In order to firm up the diagnosis in these children with very high anti-tTG titre, HLA-DQ2/DQ8 should be checked and be positive. Approximately 25-40% of white Caucasian population has HLA-DQ2/DQ8 haplotype. However, only 0.1-1% of the population will develop coeliac disease. Therefore, HLA-DQ2/DQ8 testing must not be done to 'screen' or 'diagnose' children with coeliac disease. Its use by paediatricians should be limited to children with anti-tTG>10×ULN, where the diagnosis of coeliac disease is being made on serology alone. A review of case referrals made to a tertiary paediatric gastroenterology centre in Southwest England demonstrated that HLA-DQ2/DQ8 testing is being requested inappropriately both in primary and secondary care suggesting a poor understanding of its role in diagnosis of coeliac disease. This article aims to clarify the role of HLA-DQ2/DQ8 testing for clinicians working in non-specialist settings.
authors.affiliation: 1 Consultant Paediatrician, Department of Paediatrics, Torbay Hospital, UK.
authors.forename: Siba P
authors.initials: SP
authors.lastname: Paul
authors.affiliation: 2 Senior General Practitioner, Clevedon Medical Centre, Clevedon.
authors.forename: Matthew
authors.initials: M
authors.lastname: Hoghton
authors.affiliation: 3 Consultant in Paediatric Gastroenterology, Department of Paediatric Gastroenterology, Bristol Royal Hospital for Children, UK.|4 Honorary Professor in Paediatric Gastroenterology, Joint Centre for Child and Adolescent Health, University of Bristol and University of the West of England, UK.
authors.forename: Bhupinder
authors.initials: B
authors.lastname: Sandhu
mesh_terms: D002446:Celiac Disease / Q000097:blood / Q000175:diagnosis* / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D004739:England; D005260:Female; D019204:GTP-Binding Proteins / Q000276:immunology; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006683:HLA-DQ Antigens / Q000097:blood / Q000235:genetics*; D006650:Histocompatibility Testing; D006801:Humans; D008297:Male; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases / Q000276:immunology
chemical_list: D006683:HLA-DQ Antigens; C053186:HLA-DQ2 antigen; C109756:HLA-DQ8 antigen; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins
keywords: Coeliac disease; ESPGHAN guidelines; HLA-DQ2/DQ8 typing; children; inappropriate use