Background: Obesity is a chronic condition associated with poorer cognitive
functioning. Wisconsin Card Sorting Test (WCST) is a useful tool for evaluating
executive functions. In this study, we assessed the association between dopaminergic
gene polymorphisms: DAT1 (SLC6A3), COMTVal158Met, DRD4 (48-bp variable number
of tandem repeats - VNTR) and WCST parameters to investigate the functions of the
frontal lobes in obese individuals.
Objective: To find the significant correlations between polymorphisms of DAT1,
COMTVal158Met, DRD4 and executive functions in obese subjects.
Methods: The analysis of the frequency of individual alleles was performed in 248
obese patients (179 women, 69 men). Evaluation of the prefrontal cortex function
(operating memory and executive functions) was measured with the Wisconsin Card
Sorting Test (WCST). Separate analyzes were performed in age subgroups to determine
different activities and regulation of genes in younger and older participants.
Results: Scores of WCST parameters were different in the subgroups of women and
men and in the age subgroups. Regarding the COMT gene, patients with A/A and G/A
polymorphisms showed significantly better WCST results in WCST_P, WCST_CC and
WCST_1st. Regarding DAT1 men with L/L and L/S made less non-perseverative errors,
which was statistically significant. In DRD4, significantly better WCST_1st results were
found only in older women with S allele.
Conclusion: Obtained results indicate the involvement of dopaminergic transmission in
the regulation of prefrontal cortex function. Data analysis indicates that prefrontal cortex
function may ensue, from different elements such as genetic factors, metabolic aspects
of obesity, and hormonal activity (estrogen).