The HLA-D associations of Type 1 (insulin-dependent) diabetes in Punjabi Asians in the United Kingdom

Abstract
Summary Type 1 (insulin-dependent) diabetes is less common in Asian Indians than in white Caucasoids. Forty-five Punjabi Asians with Type 1 diabetes and 96 racially matched control subjects were HLA-DR typed. DR3 was increased in diabetic patients vs control subjects (82% vs 38%, p−5) with relative risk 7.7 and etiological fraction 0.72. DR4 was increased in diabetic patients vs control subjects (31% vs 7%, pp<0.02). A 12kb fragment was associated with DR4 in both diabetic patients and control subjects. DR3 is the major susceptibility factor for Type 1 diabetes in Punjabi Asians and DR4 is a second marker. Gene probing indicates that the same DR4 subset is associated with the condition as in white Caucasoids. DR1 and its associated DQβ restriction fragments are reduced in Asian Type 1 diabetic patients making it unlikely that DR1 haplotypes carry a predisposing factor in this racial group. We conclude that the genetic component of Type 1 diabetes in Punjabis shows differences from that of the white Caucasoid population and that the lower frequency of DR4 in this population may contribute to the lower prevalence of Type 1 diabetes.