Association of paraoxonase 1 (PON1) L55M and PON1 Q192R gene polymorphisms and risk of psoriasis

BACKGROUND: Although there have been significant advances for clarifying the pathogenesis of psoriasis, exact pathogenic mechanism of the disease is still unknown. Oxidative stress is considered to be a new etiopathogenetic key factor in the pathogenesis of psoriasis, as a result of the studies performing the association between psoriasis and paraoxonase 1 (PON1) activity. In this study, we aimed to examine the possible associations between the both PON1 L55M and PON1 Q192R polymorphisms and psoriasis susceptibility and disease progression in Turkish population. METHODS: The study group consisted of 100 unrelated patients with psoriasis and 153 unrelated healthy controls with no psoriatic lesions in their personal history or on clinical examination. Genomic DNA was extracted from peripheral leukocytes from EDTA-anticoagulated blood using the High Pure Polymerase Chain Reaction Template Preparation Kit. To identify PON1 L55M and Q192R single-nucleotide polymorphisms, genotyping was performed using commercially synthesized primers and fluorescently labeled probes and the LightCycler 480 II Real-Time Polymerase Chain Reaction System. The genotyping method was based on methods developed previously for genotyping both PON1 55 and 192 polymorphisms using LightCycler real-time polymerase chain reaction technology, which relies on fluorescence resonance energy transfer. RESULTS: There was no significant difference between the PON1 L55M genotype distributions and allele frequencies of the psoriasis patients and the control group. There was a statistically significant difference between distributions of the genotype or allele frequencies of the PON1 Q192R of the patient groups and control subjects (P=0.0018 and P=0.0001, respectively). PON192Q/R polymorphisms have been found to be associated with susceptibility to psoriasis. CONCLUSIONS: This is the first report simultaneously investigating the possible associations between the PON1 L55M and PON1 Q192R polymorphisms and psoriasis susceptibility and disease progression in Turkish population. We provide evidence that PON1 Q192R polymorphisms may have an effect on the risk of psoriasis in the Turkish population.