Distribution of glyoxalase I polymorphism among Zuni Indians: the Zuni Kidney Project.
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Zuni Indians are experiencing simultaneous epidemics of type 2 diabetes mellitus (T2DM) and renal disease [Scavini, M., Stidley, C. A., Shah, V. O., Narva, A. S., Tentori, F., Kessler, D. S., et al. (2003). Prevalence of diabetes is higher among female than male Zuni Indians: Diabetes among Zuni Indians. Diabetes Care, 26 (1), 55-60; Shah, V. O., Scavini, M., Stidley, C., Tentori, F., Welty, T., Maccluer, J. W., et al. (2003). Epidemic of diabetic and nondiabetic renal disease among the Zuni Indians: The Zuni Kidney Project. Journal of the American Society of Nephrology, 14, 1320-1329]. Methylglyoxal (MG), a highly reactive, cytotoxic, cross-linking endogenous aldehyde involved in the modification of biologic macromolecules, is elevated among patients with T2DM. Glyoxalase I (Glo1) is the initial enzyme involved in the detoxification of MG. Glo1 is a dimeric enzyme with three isoforms Glo1-1, Glo2-1, and Glo2-2, resulting from a point mutation (A-->C) at position 332 of cDNA. The present study was conducted to explore the hypothesis that specific polymorphisms of the Glo1 gene are associated with diabetes and/or albuminuria in Zuni Indians. We studied four groups of Zuni Indians stratified by diabetes status and albuminuria, as assessed by the urinary albumin:creatinine ratio (UACR): Group I--normal controls; Group II--T2DM and UACR<0.03; Group III--T2DM and UACR>or=0.03; and Group IV--nondiabetic participants with UACR>or=0.03. Genomic DNA was used as template for polymerase chain reaction amplification of the Glo1 gene. Products were digested to yield 110-bp bands (homozygous, CC); 54- and 45-bp bands (homozygous, AA); or all three bands (heterozygous CA). Data on age, gender, UACR, serum creatinine, hemoglobin A1(c), serum glucose, systolic and diastolic blood pressures, and the duration of T2DM among participants in Groups II and III were analyzed using analysis of variance. A generalized linear model logistic regression analysis was used to assess the relationships between specific Glo1 polymorphisms to T2DM and UACR. All three Glo1 genotypes were present among Zuni Indians. There were no significant differences in the distributions of Glo1 genotypes among the study groups (chi-square test, P=.5590). The prevalence of Glo1 A allele was higher among diabetic participants (Groups II and III combined) than among nondiabetic participants (Groups I and IV combined) (chi-square test, P=.0233). There was an association (odds ratio=2.9; 95% confidence interval=1.3-7.2) between the Glo1 A allele and T2DM.