Although the serotonin transporter length polymorphic region (5-HTTLPR) polymorphism is an extensively-investigated genetic marker of anxiety related personality traits (neuroticism and harm avoidance) and affective disorders, effect sizes in meta-analyses are small, if present at all, and all available primary studies to date lack mandatory statistical power.
Analysis did not show any statistically significant differences in the mean levels of anxiety, and mood disorders in women in relation to genotypes of the 5-HTTLPR (SLC6A4) polymorphism and the 30-bp VNTR polymorphism in the MAO A promoter region.
Epigenetic and epistatic interactions between serotonin transporter and brain-derived neurotrophic factor genetic polymorphism: insights in depression.