Childhood obesity and the role of dopamine D2 receptor and cannabinoid receptor-1 gene polymorphisms.

OBJECTIVE

The dopaminergic and endocannabinoid systems are involved in regulation of feeding behavior. The aim of the study is to examine the possible relation between polymorphisms of the dopamine D2 receptor (DRD2) and cannabinoid receptor-1 (CNR1) genes and childhood obesity.

METHODS

A hundred obese children and 100 healthy controls were analyzed for DRD2 Taq1A and Taq1B and CNR1 1359G/A polymorphisms. Genotyping was performed by polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

There were no statistically significant differences in DRD2 Taq1A and DRD2 Taq1B genotypes or allelic frequencies between obese children and controls (p>0.05). In patients with Taq1B2 allele, morbid obesity was less frequent (p=0.010). The frequency of the A allele of CNR1 1359G/A polymorphism was significantly higher in obese children than in controls (21.0% vs. 13.0%, p=0.0166). The frequency of genotypes AG and GG of the CNR1 1359G/A SNP was different between obese children and control subjects (for AG: 34.0% vs. 22.0%, p=0.0294; for GG: 62.0% vs. 76.0%, p=0.0162, respectively).

CONCLUSIONS

No significant difference was found between genotypes and alleles of DRD2 Taq1A and DRD2 Taq1B polymorphism in patients and controls, while the CNR1 receptor 1359G/A polymorphism and the presence of the A allele may be one risk factor for susceptibility to obesity.