Association between the leptin gene 2548G/A polymorphism, the plasma leptin and the metabolic syndrome with psoriasis

Background: Psoriasis is a disorder with genetic and immunologic background. Leptin can regulate the T-helper response. Objective: Our primary goal is to study the functional polymorphism (G-2548A) of the leptin (LEP) gene in the genetic predisposition of psoriasis, and our secondary goal is to examine factors affecting plasma leptin levels in psoriasis and to compare patients with and without metabolic syndrome (MS). Methods: The study involved 94 patients with psoriasis and 100 healthy controls. Analysis of G-2548A polymorphism of the LEP gene was made by the PCR and restriction fragment length polymorphism technique. The relationship between LEP gene polymorphism and the clinical features of the patients was analysed. Plasma leptin levels and proportions of comorbidities in patients vs controls were compared. Results: In controls, the GA, AA and GG frequencies were 50%, 30% and 20%, respectively, while in patients, the distribution of genotypes was 42.5%, 20.2% and 38.3%, respectively, with significant difference (P = 0.014) between patients and controls. In patients with MS, the GG, GA and AA frequencies were 61.5%, 23.1% and 15.4%, respectively, while in patients without MS, the distribution of genotypes was 29.4%, 50% and 20.6%, respectively, with significant difference (P = 0.014) between both groups. Plasma leptin showed a significant higher levels in the patients versus the controls (P < 0.001), and among the different LEP genotypes (P < 0.001) in the patients' group. Conclusion: LEP G-2548A polymorphism could be a predictor for higher plasma leptin and increased risk of psoriasis and could be used as a marker for psoriasis-related comorbidity risk.