POLYMORPHISM AT THE RAD GENE IS NOT ASSOCIATED WITH NIDDM IN FINNS

Recently, a trinucleotide repeat polymorphism at the rad (ras associat ed with diabetes) locus (RAD1) on chromosome 16q was described in asso ciation with NIDDM in white Americans, In an attempt to replicate this finding, we screened RAD1 and another microsatellite marker at the D1 6S265 loci, which is located near the rad locus, with a radioactive po lymerase chain reaction method in 290 unrelated Finnish NIDDM patients and 270 control subjects and related the findings to measures of insu lin sensitivity, Both groups were randomly selected hom the western (1 89 NIDDM patients and 184 control subjects) and southern (101 NIDDM pa tients and 86 control subjects) parts of Finland, The allele frequency distributions of RAD1 and D16S265 did not differ between NIDDM patien ts and control subjects in the studied population groups, The genotype distribution was also analyzed by structural classes of the RAD1 poly morphism, and no difference was detected between the NIDDM and control groups, In addition, carriers of allele classes I, II, and IV (report ed to be preferentially associated with NIDDM in white Americans) did not differ from the class III homozygotes with respect to age at onset of NIDDM, BMI, or rates of insulin-stimulated glucose disposal, In co nclusion, we found no association between the rad locus and NIDDM or i nsulin resistance in Finnish NIDDM patients.