A polymorphism in the human serotonin transporter gene promoter (5-HTTLPR) is associated with anxiety and increased risk for developing depression in the face of adversity.
Human studies have suggested an association between a variable length polymorphism in the serotonin transporter gene promoter region and vulnerability to anxiety and depression.
Nevertheless, it showed that respondents with s/s genotype of the 44-bp polymorphism in the 5-HTT (SLC6A4) promoter region had the highest average anxiety levels both as a state and as a trait.
A deletion/insertion polymorphism within the 5-HT transporter (5-HTT) promoter gene (5-HTT gene-linked polymorphic region, 5-HTTLPR) is thought to be associated with several psychopathological phenotypes related to disturbed impulse control, anxiety and depression.
The low-expressing allele of the 5-HTT promoter polymorphism (HTTLPR) is associated with anxiety and with greater amygdala and other regional responses to emotional.