Background: Dopamine plays an important role in mediating the rewarding
properties in the abuse of drugs. The Taq1A polymorphism is a commonly studied DRD2
gene variant whereby carriers of the low-function T allele (T/T or T/C genotypes) show
reduced brain dopamine function. Therefore, individuals who have the DRD2 Taq1A polymorphism
will experience higher levels of drug addiction because the T allele is associated
with a reduced number of dopamine binding sites in the brain. A study of this gene
has been conducted in some areas, but there is no research for the population of Indonesia.
Objective: This study will focus on the frequency of the DRD2 Taq1A gene polymorphism
in the population of Indonesia and define its association with drug addiction.
Methods: This is a cross sectional study in which 182 subjects were divided into 91 drugaddicted
patients and 91 non-drug-addicted control subjects. The genotype analysis was
carried out by a modified allele-specific Polymerase Chain Reaction (PCR) method.
Results: The frequency of the T/T and C/T was significantly higher in the addicted than
control subjects. They are 6.6% and 63.7% compared to 0% and 3.3%. Likewise, the T allele
is more frequent in the addicted equal to 38%, compared to only 2% in the control
subjects. The frequency of the T allele between the addicted and control subjects shows a
significant difference (p-value < 0.0001; 95% CI), with the addicted being at a higher risk
of having the T allele (OR = 37.3; 95% CI [11.46-121.29]).
Conclusion: There is a significant difference in the frequency of the DRD2 Taq1A gene
polymorphism between addicted patients and control subjects. Thus, there is an association
between this gene polymorphism and the development of drug addiction with T allele
increases the predisposition to addiction.