DNA polymorphism in the uncoupling protein 1 (UCP1) gene has no effect on obesity related phenotypes in the Swedish Obese Subjects cohorts.

OBJECTIVE

To investigate the relationships between the A-G point mutation at position -3826 bp in the 5' flanking domain of the uncoupling protein 1 (UCP1 A-3826G) and some obesity phenotypes in the Swedish Obese Subjects (SOS) cohorts of obese and non-obese men and women. Previous studies have supported the hypothesis of an association between the UCP1 A-3826G polymorphism and body weight regulation in humans.

DESIGN

Case-control study comparing obese subjects from the SOS registry and a sample of the Swedish general population (body mass index (BMI) <27 kg/m2) with respect to genotype and allele frequencies of the UCP1 A-3826G polymorphism.

SUBJECTS

A total of 985 Swedish subjects including 674 obese (310 Male; 364 Female) and 311 non-obese subjects (54 Male; 257 Female) from the SOS cohorts.

MEASUREMENTS

DNA was extracted from total blood and genotyped by PCR-RFLP. Obesity-related phenotypes include weight history for SOS obese cohort and current weight, BMI, waist circumference and waist to hip ratio (WHR) for obese and normal weight subjects.

RESULTS

No significant difference in the allelic frequencies between obese and non-obese subjects (0.25 vs 0.24; P = 0.67). In both genders, current weight, BMI, waist circumference, WHR and weight gain over time (either measures of maximal weight ever achieved minus weight at 20 y or current weight minus weight at 20 y) were similar in carriers and non-carriers of the UCP1 A-3826G mutation (P>0.05). Similar results were obtained when the three genotypes were compared.

CONCLUSIONS

In contrast to what was found in other populations, the UCP1 A-3826G sequence variation is not associated with obesity-related phenotypes and weight gain over time in subjects from the SOS cohorts.