Association between LEPR gene 1019 polymorphism and the morphological characteristics in Roma populationof Croatia

Abstract

Brojna epidemiološka istraživanja su pokazala da je debljina značajan čimbenik rizika za većinu kroničnih bolesti današnjice. Leptin i leptinski receptor važni su regulatori uhranjenosti, korištenja energije i raspodjele tjelesnih masnoća. Stoga je cilj ovog rada bio testirati povezanost polimorfizma 1019 gena za leptinski receptor (gen LEPR) s morfološkim pokazateljima uhranjenosti kod romske populacije koja živi u Republici Hrvatskoj. Romi su izabrani za istraživanje zbog visoke prevalencije pretilosti i dijabetesa tipa 2 u ovoj populaciji kao i stoga što je riječ o endogamnoj osnivačkoj zajednici kod koje je moguće detektirati specifične veze između genotipa i fenotipa. Uzorak obuhvaća 401 odraslu osobu kod koje je provedena antropometrija te je uzeta krv za analizu DNA. Za određivanje genotipa korištena je metoda lančane reakcije polimerazom, a nakon toga su uzorci pocijepani restrikcijskim enzimom. Povezanost kategorijskih varijabli uhranjenosti s genotipom ispitana je Pearsonovim Chi2-testom. Povezanost mjerenih kvantitativnih varijabli s genotipom provjerena je analizom varijance (ANOVA) s PostHoc testom. Kako bi se uklonile razlike između spolova, provedeno je poravnavanje korištenjem „z-varijabli“ kreiranim unutar svakog spola zasebno. Utvrđeno je da je genotip TT LEPR polimorfizma 1019 značajan prediktor debljine u ovoj populaciji, pri čemu je posebno istaknut njegov utjecaj na centralno nakupljanje masnog tkiva kod muškaraca.Many epidemiological researches have shown that obesity is an important risk factor for most of the chronical diseases of modern age. Leptin and leptin receptors are important regulators of nutritional status, energy usage and body fat distribution. Therefore, the objective of this research was to test the association of LEPR gene polymorphism 1019 with morphological indicators of nutritional status of Roma population living in Croatia. The Roma have been chosen for research because of high prevalence of obesity, type 2 diabetes and because they are an endogamous founder community where it is possible to determine specific associations between genotype and phenotype. Research was done on 401 adult persons, whom have undergone anthropometry and whose blood samples were taken for DNA analysis. Polymerase chain reaction followed by a restriction enzyme cleavage was used to determine the genotype. The association of categorical variables of nutritional status with genotype was tested by Pearson’s Chi2-test. The association of measured quantitative variables with genotype has been checked by variance analysis (ANOVA) with PostHoc test. To remove differences between sexes, an alignment has been made by creating „z-variables“ within each sex specifically. It has been shown that TT genotype of LEPR 1019 polymorphism is an important predictor of obesity in this population, and that it also has a major impact on central fat tissue accumulation in the male population