A T cell receptor beta chain polymorphism is associated with patients developing insulin-dependent diabetes after the age of 20 years.
We have studied the BglII polymorphism near the T cell receptor beta chain constant region (TcR-C beta) gene, HLA-DR genotypes and certain autoimmune features in 102 patients with type I (insulin-dependent) diabetes. There was a significant decrease in the frequency of the 1:1 genotype (P = 0.008) and an increase in the 1:2 genotype (P = 0.03) of the BglII TcR polymorphism in the group of patients who developed type-I diabetes after the age of 20 years. This group of patients also showed an increased incidence of autoantibodies (especially islet cell antibody), a family history of diabetes and the presence of other autoimmune diseases. The frequency of this polymorphism in patients who developed type I diabetes before the age of 20 years was similar to a non-diabetic group. These results suggest that there are two genetically distinct groups of patients with type I diabetes. HLA-DR3 and HLA-DR4 genotypes were also increased in the diabetic patients but no significant difference was observed between HLA-DR genotypes, the TcR-C beta genotypes, the age of diagnosis or with other autoimmune features. Patients developing type I (insulin-dependent) diabetes after the age of 20 years have an additional genetic susceptibility for diabetes associated with the TcR-C beta gene.
McMillan
S A
SA
Regional Immunology Laboratory, Belfast City Hospital, Northern Ireland.
Graham
C A
CA
Hart
P J
PJ
Hadden
D R
DR
McNeill
T A
TA
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001323:Autoantibodies; D002648:Child; D002675:Child, Preschool; D015342:DNA Probes; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000276:immunology*; D005260:Female; D005838:Genotype; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D007223:Infant; D008297:Male; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D011948:Receptors, Antigen, T-Cell / Q000235:genetics* / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta
D001323:Autoantibodies; D015342:DNA Probes; D006684:HLA-DR Antigens; D011948:Receptors, Antigen, T-Cell; D016693:Receptors, Antigen, T-Cell, alpha-beta