engleski

Association analysis of G-2548A and A19G polimorphysms in the human leptin gene with obesity

Leptin is a protein hormone which plays an important role in the regulation of body adiposity, lipid metabolism and reproductive function. It is primarily secreted by the adipocytes and its concentration in the blood is proportional to the amount of body fat. Many leptin gene polymorphisms have been found, but their association with obesity is still controversial. We tested the polymorphisms G-2548A in promoter region and A19G in intron 1 of leptin gene for association with leptin concentration in the blood and obesity. A population-based association study was conducted in the population isolate of the Eastern Adriatic island of Vis, Croatia. Three hundred and twenty randomly selected subjects from the Vis population were genotyped. Obesity was defined as BMI≥ 30 kg/m2. The results revealed significant association of G-2548A variant and leptin concentration in a codominant pattern (p=0.026). The ancestral G allele which displays as a minor allele in the Vis population (frequency of 0.44) was associated with higher leptin levels. The leptin concentration was significantly higher in the obese (60.1 ng/ml, N=244), than in the non-obese group (20.7 ng/ml, N=76) and it was more than three times higher in women (44.0 ng/ml) compared to men. However, no association of G-2548A and A19G polymorphisms with obesity was found (with leptin concentration, sex and age as covariates). The results indicate that the studied polymorphisms are not relevant markers for common obesity in this isolated population, but were found to influence the leptin concentration which is an obesity-related phenotype.

leptin; polimorphysm; isolated populations

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