INVESTIGATING THE ROLE OF DOPAMINE SIGNALING GENE POLYMORPHISMS AND PREVALENCE OF HUMAN ANELLOVIRUSES INFECTION IN SUBSTANCE ABUSE

Abstract

The dopaminergic system plays a major role in consolidating the effects and dependence of abused substances. Unlike monogenic diseases, psychiatric disorders – including substance abuse and addiction – are multifactorial disorders in which genetic factors, with varying contributions to the phenotype, and environmental factors are involved. This study aimed to investigate the association between polymorphisms in genes involved in the dopaminergic signaling pathway and substance abuse, as well as to assess the prevalence of human anelloviruses. Individuals hospitalized for substance abuse (n = 15) and healthy subjects (n = 15) were recruited for the study. Blood samples were collected and used for isolating DNA and genotyping two polymorphisms in dopamine signaling genes (i.e., DRD2 TaqI A, DAT1 VNTR) using PCR-RFLP. Anelloviral DNA was detected using hemi-nested PCR. The distribution of polymorphisms did not differ from Hardy-Weinberg equilibrium in the investigated groups. A slightly higher frequency of the A1 allele of DRD2 TaqI A polymorphism was found in the substance abuse group, consistent with literature. The DAT1 VNTR 12R allele associated with lower expression of DAT1 and slower dopamine reuptake at the synapse level, appears to be protective against this type of behavior. Additionally, anelloviral DNA was present in all study participants, in line with previous reports. DAT1 VNTR genotypes might be associated with substance abuse. However, replication of results in larger groups, study of other genes, environmental factors, and their interactions are important to obtain a broader understanding of this behavior.