Background and Aims

TCF7L2 gene encodes a transcription factor expressed in pancreatic β cells that regulates insulin production and processing. It is assumed that type 2 diabetes risk gene TCF7L2 affects the response to diet therapy.

We aimed to assess an effect of the single nucleotide polymorphism (SNP) rs7903146 T/C in the TCF7L2 gene on the change of bioimpedance parameters in overweight patients who followed a generally accepted for obesity therapeutic diet for 3 months.

Methods

The study implicated 17 overweight or obese patients (15 women and 2 men) aged 23 to 60 years (average BMI on admission – 34.1±5.6 kg/m²). Within 3 months, all patients have followed a balanced therapeutic diet with the exception of easily digestible and limited digestible carbohydrates and fats. Patient genotyping data were compared with the European population (Project "1000 Genomes", n = 503). DNA was extracted from a venous blood. Gene polymorphisms were identified by real-time PCR (CFX96, USA).

Results

The observed genotype distribution was consistent with the Hardy-Weinberg equilibrium (p>0.05) and was not significantly different from the European frequency distribution. CC homozygotes of the SNP demonstrated a significant decrease in body cell mass (BCM) and total water (in kg) after 3 months of diet therapy compared to the T-allele carriers (p=0.013 and p=0.018, respectively).

Conclusions

Carriers of risk allele T demonstrated a better response to diet therapy manifested in BCM gain. More detailed study may suggest a suitable diet to compensate the adverse effect of genotype in risk allele carriers.