title: HLA-DQA1*0501 and DQB1*02 homozygosity and disease susceptibility in Spanish coeliac patients.
abstract: Coeliac disease (CD) susceptibility is strongly associated with HLA-DQA1*0501 and DQB1*02 alleles. There are discordant reports on whether homozygosity increases the risk. We genotyped HLA-DQA1*0501 and DQB1*02 in 50 CD patients, 100 parents, and 50 controls. Most patients (96%) were positive for DQA1*0501 (RR = 18.07, p < 0.001), 94% for DQB1*02 (RR = 17.55, p < 0.001), and 92% for both alleles together (RR = 31.82, p < 0.001). DQA1*0501 was found in 52% of controls, DQB1*02 in 44%, and only 24% had both alleles. Patients homozygosity or heterozygosity was estimated by assessing-in each case-whether one or both parents were carriers of the allele of risk. The frequencies of parents both positive for DQA1*0501 (58%) and for DQB1*02 (53.1%) were higher than expected by the fact that the proband is a carrier. These findings suggest that the frequency of homozygosity is increased among CD patients, and therefore, homozygosity for either DQA1*0501 or DQB1*02 represents a risk factor added to the fact of being a carrier.
authors.affiliation: University of Valladolid, Department of Paediatrics, Valladolid, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Arranz
authors.forename: J J
authors.initials: JJ
authors.lastname: Telleria
authors.forename: A
authors.initials: A
authors.lastname: Sanz
authors.forename: J F
authors.initials: JF
authors.lastname: Martin
authors.forename: M
authors.initials: M
authors.lastname: Alonso
authors.forename: C
authors.initials: C
authors.lastname: Calvo
authors.forename: A
authors.initials: A
authors.lastname: Blanco-Quirós
mesh_terms: D000483:Alleles; D002446:Celiac Disease / Q000235:genetics* / Q000276:immunology; D002675:Child, Preschool; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006683:HLA-DQ Antigens / Q000235:genetics*; D059848:HLA-DQ alpha-Chains; D059866:HLA-DQ beta-Chains; D006720:Homozygote; D006801:Humans; D008297:Male
chemical_list: D006683:HLA-DQ Antigens; D059848:HLA-DQ alpha-Chains; D059866:HLA-DQ beta-Chains; C069050:HLA-DQA1 antigen; C069051:HLA-DQB1 antigen