Analysis of manganese superoxide dismutase (MnSOD Ala-9Val) and glutathione peroxidase (GPx1 Pro 198 Leu) gene polymorphisms in psoriasis

Recent studies have suggested the involvement of increased reactive oxygen species levels and decreased antioxidant system functions in psoriasis pathogenesis. In this study, we aimed to examine to investigate possible associations between the manganese superoxide dismutase (MnSOD Ala-9Val) and glutathione peroxidase (GPx1 Pro198Leu) polymorphisms and psoriasis susceptibility and disease progression in a Turkish population. The study group consisted of 100 unrelated patients with psoriasis and 167 unrelated healthy controls. Genomic DNA was extracted from peripheral leukocytes of whole blood which were obtained from all patients and control subjects. Genotyping was performed to identify MnSOD Ala-9Val and GPx1 Pro198Leu polymorphisms by a method based on PCR amplification and detection of polymorphisms with hybridization probes labeled with fluorescent dyes. Genotype and allele frequencies were compared between patients with psoriasis and 106 healthy control subjects. There was no significant difference between the MnSOD Ala-9Val single nucleotide polymorphism (SNP) genotype distributions and allele frequencies of the psoriasis patients and the control group (p = 0.99 and p = 0.89, respectively). There was also no significant difference between distributions of the genotype or allele frequencies of the GPx1 Pro198Leu SNP of the patient groups and control subjects (p = 0.99 and p = 0.96, respectively). Also, no significant difference was found between clinical severity of psoriasis and MnSOD Ala-9Val and GPx1 Pro198Leu polymorphism. This is the first report investigating the possible associations between the MnSOD Ala-9Val and GPx1 Pro198Leu polymorphisms and psoriasis susceptibility and disease progression in the Turkish population even if no significant difference was found between patient groups and control subjects. Further studies with large cohort on different populations and ethnicities will be able to better clarify the association.