title: Frequency of HLA-DQB1*0201/02 and DQB1*0302 alleles and tissue transglutaminase antibody seropositivity in children with type 1 diabetes mellitus.
abstract: BACKGROUND
  Patients with type 1 diabetes mellitus (T1DM) have an increased risk of celiac disease (CD). Both diseases have a common genetic susceptibility locus in the human leukocyte antigen (HLA) class II alleles. Testing for tissue transglutaminase antibodies (anti-tTG) is highly accurate for a CD diagnosis.
  
  
  OBJECTIVE
  To determine the frequency of HLA-DQB1*0201/02 and DQB1*0302 alleles and anti-tTG seropositivity in children with T1DM.
  
  
  METHODS
  Forty-six children with T1DM (male:female=24:22; mean age 12±3.7 years) without significant digestive symptoms were enrolled. The mean duration of diabetes was 5±3.5 years. Serum anti-tTG IgA and IgG as well as HLA-DQ2 (DQB1*0201/02) and -DQ8 (DQB1*0302) alleles were analyzed. The allele frequencies were compared with those in controls, which included 124 normal Thai individuals, as reported in our previous study.
  
  
  RESULTS
  All subjects were negative for anti-tTG IgG. Only one patient (2.2%) was positive for anti-tTG IgA (38.5 U/mL; cut-off 15 U/mL). Although this patient was also heterozygous for HLA-DQ2 and was asymptomatic for CD, he declined endoscopic confirmation. Twenty-nine of 46 patients carried HLA-DQ2 and/or -DQ8 heterodimers. HLA-DQB1*0201/02 and HLA-DQB1*0302 allele frequencies were significantly higher (27% and 14%) in T1DM patients compared with normal controls (13.3% and 7.3%; P<0.001 and P=0.002, respectively).
  
  
  CONCLUSIONS
  A significantly greater frequency of DQB1*0201/02 and DQB1*0302 alleles were present in children with T1DM compared with the control group. This indicates a potentially important role of these alleles in the development of T1DM. The prevalence of CD screening by serologic testing is negligible in Thai children with T1DM.
authors.affiliation: Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Thailand.
authors.forename: Thanita
authors.initials: T
authors.lastname: Thammarakcharoen
authors.affiliation: Center of Excellence in Immunology and Immune-mediated Diseases, Department of Microbiology, Faculty of Medicine, Chulalongkorn University.
authors.forename: Nattiya
authors.initials: N
authors.lastname: Hirankarn
authors.affiliation: Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Thailand.
authors.forename: Taninee
authors.initials: T
authors.lastname: Sahakitrungruang
authors.affiliation: Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Thailand.
authors.forename: Thanunrat
authors.initials: T
authors.lastname: Thongmee
authors.affiliation: National Blood Center, The Thai Red Cross Society.
authors.forename: Pavinee
authors.initials: P
authors.lastname: Kuptawintu
authors.affiliation: National Blood Center, The Thai Red Cross Society.
authors.forename: Sriprapai
authors.initials: S
authors.lastname: Kanoonthong
authors.affiliation: Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Thailand.
authors.forename: Voranush
authors.initials: V
authors.lastname: Chongsrisawat
mesh_terms: D000293:Adolescent; D000483:Alleles; D001323:Autoantibodies / Q000097:blood*; D002446:Celiac Disease / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics* / Q000276:immunology*; D005260:Female; D019204:GTP-Binding Proteins / Q000276:immunology*; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006683:HLA-DQ Antigens / Q000235:genetics; D059866:HLA-DQ beta-Chains / Q000235:genetics*; D006239:Haplotypes; D006650:Histocompatibility Testing; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D006683:HLA-DQ Antigens; D059866:HLA-DQ beta-Chains; C053186:HLA-DQ2 antigen; C069051:HLA-DQB1 antigen; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins