ObjectiveCytochrome P450 (CYP) 2J2 plays an important role in the biosynthesis of the biologically activecis-epoxyeicosatrienoic acids. An allelic variant namedCYP2J2*6, which encodes an enzyme that is almost inactive in the metabolism of arachidonic acid, has recently been described. We investigated the frequency of theCYP2J2*6 variant in a Caucasian population and the relationship between this polymorphism and the development of micro- and macrovascular complications and hypertension in patients with type 1 or type 2 diabetes mellitus.MethodsGenomic DNA was extracted from peripheral blood cells and the fragment containing the A/T single nucleotide polymorphism at position 25 661 in exon 8 of theCYP2J2gene was amplified. The 532 bp amplified product was subsequently digested withTsp509I and analyzed on 12% polyacrylamide gel electrophoresis.ResultsIn the whole population, the frequency of theCYP2J2*6 allele was 0.0064 and the frequency of theCYP2J2*1 allele was 0.9936. Genotype distribution did not show significant differences between controls and patients with type 1 or type 2 diabetes. No homozygotes forCYP2J2*6 allele were found. No association was found between this allele and complications or hypertension in either type of diabetes.ConclusionTheCYP2J2*6 allele is rare in the Caucasian population, and no association is inferred between this allelic variant and diabetic complications.