−308 Nco I polymorphism of tumour necrosis factor α in overweight Caucasians

Abstract 

We investigated whether a polymorphism in the promoter region of the TNFα gene (−308 A/G) is associated with reduced weight loss in obese Australian subjects on an energy restricted diet. 189 healthy subjects and 91 subjects with type II diabetes were genotyped for the −308 Nco I polymorphism using PCR-RFLP techniques. A subset of these subjects (211 females and 45 males), were placed on a 30% energy restricted diet (6200 kJ) for 12 weeks. Subjects were assessed every 2 weeks and changes in body weight, waist circumference and BMI were used as determinants of weight loss. Fasting plasma was analysed for glucose, insulin, lipids and free fatty acids. 64% of subjects were GG homozygotes, 31% were AG heterozygotes and 5% were AA homozygotes. There was no significant difference between the allele frequency in healthy subjects (0.21) and type 2 diabetic patients (0.24). The presence of the −308 A/G polymorphism did not significantly influence initial BMI, the amount of weight lost (GG, 8.1±0.65 kg, AG, 6.9±0.77 kg, AA, 7.6±0.12 kg), waist circumference or any metabolic variable. The AA variant at position −308 in the promoter region of the TNFα gene does not influence the amount of weight lost in overweight and obese men and women on a 30% energy restricted diet.

Keywords: Tumour necrosis factor alpha polymorphism, Obesity, Weight loss

Abbreviations: BMI, body mass index, HDL, high density lipoprotein, TNFα, tumour necrosis factor alpha