title: Interaction between tumor necrosis factor-α gene -308G/A promoter and leptin receptor gene Lys656Asn single-nucleotide polymorphisms: effect on serum leptin concentrations.
abstract: OBJECTIVE
  The aim of our study was to investigate the interaction between the tumor necrosis factor-α (TNF-α) gene -308G/A promoter and the leptin receptor (LEPR) gene Lys656Asn polymorphisms and their effects on serum leptin levels in obese subjects.
  
  
  METHODS
  A population of 237 obese patients was analyzed prospectively. Bipolar electrical bioimpedance, a biochemical analysis and serum concentrations of leptin and TNF-α were assessed.
  
  
  RESULTS
  The number of subjects with both mutations was 21 (8.86%). Subjects carrying the mutant LEPR genotype had higher concentrations of leptin than those with the wild-type LEPR genotype only when they also carried the mutant TNF-α genotype (G308A or A308A) (82.7 ± 63 vs. 147.6 ± 89 ng/ml; p < 0.05). In subjects with TNF-α G308G, multivariate analysis with leptin as a dependent variable revealed fat mass as an independent predictor in the model (F = 15.4; p < 0.05), with an increase of 4.1 ng/ml (95% CI 2.5-5.6) per kilogram of fat mass. The same was seen in subjects with TNF-α G308A and A308A genotypes, with an increase in leptin levels of 3.56 ng/ml (95% CI 1.8-5.3) per kilogram fat mass.
  
  
  CONCLUSIONS
  There is an interaction between TNF-α gene G308A promoter and LEPR gene Lys656Asn polymorphisms, with higher concentrations of leptin in the G308A and A308A genotypes combined with the mutant LEPR genotype.
authors.affiliation: Institute of Endocrinology and Nutrition, School of Medicine and Unit of Investigation, Hospital Rio Hortega, University of Valladolid, C/Los Perales 16, Simancas, Spain. dadluis@yahoo.es
authors.forename: D A
authors.initials: DA
authors.lastname: de Luis
authors.forename: R
authors.initials: R
authors.lastname: Aller
authors.forename: O
authors.initials: O
authors.lastname: Izaola
authors.forename: M
authors.initials: M
authors.lastname: Gonzalez Sagrado
authors.forename: R
authors.initials: R
authors.lastname: Conde
authors.forename: E
authors.initials: E
authors.lastname: Romero
mesh_terms: D000328:Adult; D015992:Body Mass Index; D005260:Female; D005838:Genotype; D006801:Humans; D020738:Leptin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D011446:Prospective Studies; D054411:Receptors, Leptin / Q000235:genetics*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
chemical_list: D020738:Leptin; D054411:Receptors, Leptin; D014409:Tumor Necrosis Factor-alpha