Dopamine Genes (DRD2/ANKK1-TaqA1 and DRD4-7R) and Executive Function: Their Interaction with Obesity

<div><p>Obesity is a multifactorial disease caused by the interaction between genotype and environment, and it is considered to be a type of addictive alteration. The A1 allele of the DRD2/ANKK1-TaqIA gene has been associated with addictive disorders, with obesity and with the performance in executive functions. The 7 repeat allele of the DRD4 gene has likewise been associated with the performance in executive functions, as well as with addictive behaviors and impulsivity. Participants were included in the obesity group (N = 42) if their body mass index (BMI) was equal to or above 30, and in the lean group (N = 42) if their BMI was below 25. The DRD2/ANKK1-TaqIA and DRD4 VNTR polymorphisms were obtained. All subjects underwent neuropsychological assessment. Eating behavior traits were evaluated. The ‘DRD2/ANKK1-TaqIA A1-allele status’ had a significant effect on almost all the executive variables, but no significant ‘DRD4 7R-allele status’ effects were observed for any of the executive variables analyzed. There was a significant ‘group’ x ‘DRD2/ANKK1-TaqIA A1-allele status’ interaction effect on LN and ‘group’ x ‘DRD4 7R-allele status’ interaction effect on TMT B-A score. Being obese and a carrier of the A1 allele of DRD2/ANKK1-TaqIA or the 7R allele of DRD4 VNTR polymorphisms could confer a weakness as regards the performance of executive functions.</p> </div

Effect of ‘group’, ‘DRD4 7R-allele status’ and their interactions with executive functions and eating behavior.

<p>Results are controlled for gender and depression scores.</p>§<p>raw score.</p><p>SD = Standard deviation; LN = Letters and Numbers (WAIS III); SDMT = Symbol Digit Modalities Test; TMT = Trail making Test; WCST = Wisconsin Card Sorting Test; BITE = Bulimic lnvestigatory Test Edinburgh; 3FEQ = 3-factor Eating Questionnaire.</p>*<p>p<0.05; **p<0.01; ***p<0.001; Ef S = effect size: ήή² = 0.0099, small effect; ήή² = 0.0588, medium effect; ήή² = 0.1379, large effect.</p

Demographic and clinic characteristics in obese subjects.

<p>C = Caucasian; H = Hispanic; SAP = Systolic arterial pressure; DAP = Diastolic arterial pressure; TGL = blood triglycerides (mmol/l); CHO = blood cholesterol (mmol/l); Gly = Glycemia (mmol/l).</p

Effect of ‘group’, ‘DRD2/ANKK1-TaqIA A1-allele status’ and their interactions with executive functions and eating behavior.

<p>Results are controlled for depression scores.</p>§<p>raw score.</p><p>SD = Standard deviation; LN = Letters and Numbers (WAIS III); SDMT = Symbol Digit Modalities Test; TMT = Trail making Test; WCST = Wisconsin Card Sorting Test; BITE = Bulimic lnvestigatory Test Edinburgh; 3FEQ = 3-factor Eating Questionnaire.</p>*<p>p<0.05; **p<0.01; ***p<0.001; Ef S = effect size: ή² = 0.0099, small effect; ή² = 0.0588, medium effect; ή² = 0.1379, large effect.</p

‘Group’ x ‘DRD4 VNTR 7R- allele status’ interaction effect on TMT B-A score.

<p>Performance in TMT B-A is obtained by regressing depression and gender on the dependent variable, and then saving the standardized residual from this model.</p

Comparison between obese and control subjects in demographics, neuropsychological and questionnaire scores.

§<p>is for raw score.</p><p>F = female; M = male; BMI =  body mass index; HADS =  Hamilton Anxiety and Depression Scale; LN =  Letters and Numbers (WAIS III); SDMT =  Symbol Digit Modalities Test; TMT =  Trail making Test; WCST =  Wisconsin Card Sorting Test; BITE =  Bulimic lnvestigatory Test Edinburgh; 3FEQ = 3-factor Eating Questionnaire.</p

Demographic and clinic characteristics in normal-weight subjects.

<p>C = Caucasian; H = Hispanic; SAP = Systolic arterial pressure; DAP = Diastolic arterial pressure; TGL = blood triglycerides (mmol/l); CHO = blood cholesterol (mmol/l); Gly = Glycemia (mmol/l).</p

Frequencies of DRD4 exon 3 VNTR alleles and genotypes in obese and control subjects.

<p>Frequencies of DRD4 exon 3 VNTR alleles and genotypes in obese and control subjects.</p

Frequencies of DRD2/ANKK1 alleles and genotypes in obese and control subjects.

<p>Frequencies of DRD2/ANKK1 alleles and genotypes in obese and control subjects.</p

‘Group’ x ‘DRD2/ANKK1-TaqIA A1-allele status’ interaction effect on BITE symptoms.

<p>Scores in BITE symptoms are obtained by regressing depression on the dependent variable, and then saving the standardized residual from this model.</p