Celiac Disease Genetics: Current Concepts and Practical Applications Ludvig M. Sollid, Benedicte A. Lie  Clinical Gastroenterology and Hepatology  Volume 3, Issue 9, Pages 843-851 (September 2005) DOI: 10.1016/S1542-3565(05)00532-X Copyright © 2005 American Gastroenterological Association Terms and Conditions

Figure 1 Schematic depiction of the multifactorial etiology of celiac disease. Environmental components (including gluten) and several genetic factors (including HLA) are involved in the development of celiac disease. There are interactions between genetic and environmental factors (eg, HLA and gluten), and there might also be interactions between the various predisposing genetic factors (ie, epistasis) and environmental risk factors. Clinical Gastroenterology and Hepatology 2005 3, 843-851DOI: (10.1016/S1542-3565(05)00532-X) Copyright © 2005 American Gastroenterological Association Terms and Conditions

Figure 2 HLA association in celiac disease. The great majority of the patients carry the DQA1*05 and DQB1*02 alleles located in cis on the DR3-DQ2 haplotype or in trans on the DR5-DQ7 and DR7-DQ2 haplotypes. A minority of the patients carry DQA1*03 and DQB1*0302 encoded by the DR4-DQ8 haplotype. The DQα chains encoded by DQA1*0501 and DQA1*0505 differ by one residue in the leader peptide, and the DQβ chains encoded by DQB1*0201 and DQB1*0202 differ by one residue in the membrane proximal domain. It is unlikely that these differences have any functional consequence. Notably, the DR3 allele of the DR3-DQ2 is also termed DR17, and DR5 includes the variants DR11 and DR12. Clinical Gastroenterology and Hepatology 2005 3, 843-851DOI: (10.1016/S1542-3565(05)00532-X) Copyright © 2005 American Gastroenterological Association Terms and Conditions

Figure 3 HLA genotyping test in relation to celiac disease. The distribution of positive and negative test results among celiac disease patients and unaffected individuals from 4 different HLA genotyping tests: (A) scoring for presence of DQB1*02, (B) scoring for presence of the DQ2 heterodimer (DQA1*05 and DQB1*02), (C) scoring for presence of the DQ2 heterodimer or DQ8, and (D) scoring for presence of the DQ2 heterodimer, DQ8, or one of the alleles of the DQ2 heterodimer (DQA1*05 or DQB1*02). Clinical Gastroenterology and Hepatology 2005 3, 843-851DOI: (10.1016/S1542-3565(05)00532-X) Copyright © 2005 American Gastroenterological Association Terms and Conditions