Hep-G2 glucose transporter gene polymorphism in Caucasian, black, Hispanic and Japanese patients with NIDDM

DNA from non-diabetic Caucasians (n = 16), Blacks (n = 22), Hispanics (n = 13) and Japanese (n = 21), as well as DNA from 34 Caucasian, 19 Black, 19 Hispanic and 20 Japanese non-insulin-dependent diabetes mellitus (NIDDM) patients were examined for restriction fragment length polymorphism (RFLP) after digestion with enzymes BglII and XbaI, and hybridization with the glucose transporter probe, hGT2-2. There were significant differences in the incidence of the RFLPs between Caucasians and Blacks, both controls and patients with NIDDM. Digestion with XbaI revealed a higher incidence of the homozygotic state for allele I in NIDDM Caucasians (12 vs. 0%) than in controls. In NIDDM Blacks and Hispanics, we found a high incidence of a combination of two traits: 42% of the Black and 47% of the Hispanic NIDDM patients were homozygous for the BglII allele I and heterozygous for XbaI. Only 23% of non-NIDDM Blacks or Hispanics had this combination (P less than 0.05). There was no association between RFLP frequency and NIDDM among Japanese subjects. These data support the influence of race on both BglII and XbaI RFLPs. The homozygotes for XbaI in Caucasians and the presence of two specific traits in Blacks and Hispanics appear with higher frequency in NIDDM.