Relationship between premature ejaculation and genetic polymorphisms of the dopamine transporter gene (SLC6A3)

What’s known on the subject? and What does the study add? The process of ejaculation is highly influenced by genetic and neurobiological factors. Central dopaminergic drugs facilitate ejaculation. Genetic variation in SLC6A3 may alter the expression of dopamine transporter gene (DAT). This study evaluated the associations between genetic polymorphisms of the DAT and PE. A statistically significant association was observed between the presence of 9‐repeat allele and 9/10 genotype and PE. The presence of 7‐repeat allele had protective effect against PE. OBJECTIVE • To investigate the possible relationships between premature ejaculation (PE) polymorphisms in the dopamine transporter (DAT) gene (SLC6A3, DAT1), which has a polymorphic 40 base pair (40 bp) variable number of tandem repeats (VNTR) sequence in the 3′‐untranslated region (3′ VNTR). PATIENTS AND METHODS • Cohorts of 270 Iranian men with PE and 266 age‐matched healthy Iranian subjects were genotyped for the DAT1‐VNTR polymorphism. RESULTS • The 10‐repeat allele frequencies were similar in the control (90.2%) and patient groups (88.5%) ( P = 0.8). • A statistically significant association was observed between the presence of the nine‐repeat allele and PE (chi‐squared test = 4.346, odds ratio [OR] = 2.46, 95% confidence interval [CI] = 1.57–3.15, P = 0.026). • The frequencies of the 9/10 genotype were also significantly higher in the PE patients than in normal controls (chi‐squared test = 4.466, OR = 2.47, 95% CI = 1.52–3.21, P = 0.028). The presence of the seven‐repeat allele had a protective effect against PE (chi‐squared test = 2.324, OR = 0.62, 95% CI = 0.47–0.89, P = 0.034). CONCLUSIONS • The findings of the present study suggest that DAT1‐VNTR polymorphisms resulting in higher dopamine concentrations were associated with vulnerability to PE. • Further studies are needed to replicate these results and to evaluate the role of inconsistency in the DAT genes and how this affects the development of PE.