title: Genetic and immunological characteristics of Type I diabetes mellitus in an Indo-Aryan population.
abstract: OBJECTIVE
  Our aim was to characterise the genetic and immunological features associated with Type I (insulin-dependent) diabetes mellitus in a cohort of Indo-Aryan children resident in the United Kingdom.
  
  
  METHODS
  Children with Type I diabetes (n = 53), unaffected first-degree relatives (n = 146) and unrelated healthy control children (n = 54) were typed for alleles of the HLA-DRB1, HLA-DQA1 and HLA-DQB1 genes. Islet cell antibodies and antibodies to glutamic acid decarboxylase, protein tyrosine phosphatase-2 (IA-2ic) and insulin were measured in the diabetic and control children.
  
  
  RESULTS
  The DRB1*03.DQA1*05.DQB1*02 haplotype was positively associated with the disease, occurring in 78% of diabetic children compared with 22.6 % of healthy children (p(c) < 2.4 x 10(-5)). In simplex families, this haplotype was transmitted more frequently to the diabetic children than to their unaffected siblings (p < 1 x 10(-4)). The DRB1*04.DQA1* 03.DQB1*0302 haplotype was also transmitted preferentially to the diabetic probands (p < 0.025) but was not associated with disease in the case control study. Islet-related autoantibodies were detected in 89.6 % of diabetic patients compared with 11.8 % of control children (p < 1 x 10(-6)). Although protein tyrosine phosphatase-2 autoantibodies were detected more frequently among DRB1*04-positive diabetic patients compared with patients lacking this allele, the overall frequency of these autoantibodies was lower than observed in Europid diabetic subjects. This could reflect the absence of a disease association with DRB1*04 in the Indo-Aryan cohort.
  
  
  CONCLUSIONS
  Type I diabetes in our Indo-Aryan cohort is similar to the disease observed in Anglo-Europeans but has important immunogenetic differences. The low frequency of protein tyrosine phosphatase-2 autoantibodies among the Indo-Aryan diabetic children could have important implications for the design of future strategies for disease prediction in this population.
authors.affiliation: Department of Medicine, University of Birmingham, UK.
authors.forename: M A
authors.initials: MA
authors.lastname: Kelly
authors.forename: N S
authors.initials: NS
authors.lastname: Alvi
authors.forename: N J
authors.initials: NJ
authors.lastname: Croft
authors.forename: C H
authors.initials: CH
authors.lastname: Mijovic
authors.forename: G F
authors.initials: GF
authors.lastname: Bottazzo
authors.forename: A H
authors.initials: AH
authors.lastname: Barnett
mesh_terms: D000293:Adolescent; D001323:Autoantibodies / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics* / Q000276:immunology*; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology; D006683:HLA-DQ Antigens / Q000235:genetics*; D059848:HLA-DQ alpha-Chains; D059866:HLA-DQ beta-Chains; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006239:Haplotypes; D006801:Humans; D007194:India / Q000208:ethnology; D007223:Infant; D007328:Insulin / Q000276:immunology; D007515:Islets of Langerhans / Q000276:immunology; D008297:Male; D010154:Pakistan / Q000208:ethnology; D054648:Protein Phosphatase 2; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases / Q000276:immunology
chemical_list: D001323:Autoantibodies; D006683:HLA-DQ Antigens; D059848:HLA-DQ alpha-Chains; D059866:HLA-DQ beta-Chains; C069050:HLA-DQA1 antigen; C069051:HLA-DQB1 antigen; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; D007328:Insulin; D054648:Protein Phosphatase 2; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases; D005968:Glutamate Decarboxylase