We have carried out a detailed reexamination of the genetics of the APM1 locus and its contribution to the genetic basis of type 2 diabetes susceptibility in the French Caucasian population. The G allele of single nucleotide polymorphism ؊11426 in the APM1 promoter showed modest association with type 2 diabetes (odds ratio 1.44 [95% CI 1.04 -1.98]; P ‫؍‬ 0.03), providing corroborative evidence that single nucleotide polymorphisms in the APM1 promoter region contribute to the genetic risk of

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... genetic risk of type 2 diabetes. A "sliding window" analysis identified haplotypes 1-1-1, 1-1-1-1, and 1-1-1-1-1 as being strongly protective against type 2 diabetes (P < 0.0001). Evidence is presented that the APM1 gene is a locus of low linkage disequilibrium, high haplotype diversity, and high recombination. We were unable to obtain data to support the hypothesis that genetic variation in the APM1 gene is a major contributor to the type 2 diabetes linkage result at chromosome 3q27. Finally, in families with early-onset type 2 diabetes, we obtained suggestive evidence of a linkage peak for serum adiponectin levels (logarithm of odds ‫؍‬ 2.1) that closely matched the position of the type 2 diabetes linkage peak. This result indicated that the type 2 diabetes susceptibility locus at 3q27 influences both genetic predisposition to type 2 diabetes and serum adiponectin levels in patients with type 2 diabetes.