Previously, we performed a genome scan for type 2 diabetes (T2DM) using 638 African-American (AA) affected sibling pairs from
247 families; non-parametric linkage analysis suggested evidence of linkage at 6q24–27 (LOD 2.26). To comprehensively evaluate
this region, we performed a two-stage association study by first constructing a SNP map of 754 SNPs selected from HapMap on
the basis of linkage disequilibrium (LD) in 300 AAT2DM end-stage renal disease (ESRD) subjects, 311 AA controls, 43 European
American controls and 45 Yoruba Nigerian samples (Set 1). Replication analyses were conducted in an independent population
of 283 AA T2DM-ESRD subjects and 282 AA controls (Set 2). In addition, we adjusted for the impact of admixture on association
results by using ancestry informative markers (AIMs). In Stage 1, 137 (18.2%) SNPs showed nominal evidence of association
(
P < 0.05) in one or more of tests of association: allelic (
n = 33), dominant (
n = 36), additive (
n = 29), or recessive (
n = 34) genotypic models, and 2- (
n = 47) and 3-SNP (
n = 43) haplotypic analyses. These SNPs were selected for follow-up genotyping. Stage 2 analyses confirmed association with
a predicted 2-SNP “risk” haplotype in the
PARK2 gene. Also, two intergenic SNPs showed consistent genotypic association with T2DM-ESRD: rs12197043 and rs4897081. Combined
analysis of all subjects from both stages revealed nominal associations with 17 SNPs within genes, including suggestive associations
in
ESR1 and
PARK2. This study confirms known diabetic nephropathy loci and identifies potentially novel susceptibility variants located within
6q24–27 in AA.