Phenotype determination of a common Pro-Leu polymorphism in human glutathione peroxidase 1

Oxidative stress has been implicated in human illness such as cardiovascular and neurodegenerative disease. The genetic mechanisms involved are only poorly understood. Here we describe the determination of the allelic frequency and phenotype of a common polymorphism in Se-dependent glutathione peroxidase 1 (GPX1) in Finnish/Swedish populations. A proline/leucine variant occurs at position 197 close to the C-terminus of the protein. The more common allele encoding the Pro variant is present at 59% in a Finnish/Swedish population (n = 66) and at 73% in a Swedish population (n = 315). The genotypes encoding Pro/Pro, Pro/Leu, and Leu/Leu are distributed according to the Hardy-Weinberg relationship. The Swedish population consisted of 101 stroke cases and 214 controls. No significant association between allele frequency and risk to suffer from stroke was evident. Erythrocyte GPX activity was determined in the Finnish/Swedish population and no significant differences were obtained between the genotypes. It can be concluded that the Pro/Leu genetic variation does not appear to compromise the defense against oxidative stress in red blood cells nor to be associated with stroke.