Research Article

HLA-DR typing in identical twins with insulin-dependent diabetes: difference between concordant and discordant pairs.

Br Med J (Clin Res Ed) 1983; 286 doi: (Published 22 January 1983) Cite this as: Br Med J (Clin Res Ed) 1983;286:253
  1. C Johnston,
  2. D A Pyke,
  3. A G Cudworth,
  4. E Wolf


    A total of 106 pairs of identical twins, of whom 56 were concordant and 50 discordant for insulin-dependent diabetes, were typed for HLA-DR. In both the concordant and discordant groups there was a high prevalence of the antigens DR3 and DR4, a low prevalence of DR5 and DR7, and a virtual absence of DR2. The heterozygous phenotype DR3,DR4 was more prevalent in concordant than discordant pairs. This was therefore the first demonstration of a genetic difference between concordant and discordant identical twin pairs. These findings suggest that possession of both DR3 and DR4 antigens confers a greater genetic predisposition to insulin-dependent diabetes than does the possession of either antigen alone.