What you carry at this position in your DNA and what research says about it.
Serotonin and Mood: 6/10 evidence, 6 publications.
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Sample genotype (not yours): G/G
Higher Risk of Depressive Symptoms
Carrying two copies of the minor G allele is linked to increased depressive symptoms and higher levels of inflammatory markers. This combination may affect how the brain regulates serotonin and immune responses.
What this genotype means: Higher vulnerability to depressive symptoms; Elevated levels of the inflammatory marker IL-6.
Sample genotype (not yours): G/T
Carrying one copy of the minor G allele is associated with elevated depressive symptoms and higher systemic inflammation. This genetic profile may influence serotonin transporter efficiency and immune signaling.
What this genotype means: Increased susceptibility to depressive symptoms; Slightly elevated inflammatory markers.
Sample genotype (not yours): T/T
Typical Risk of Depressive Symptoms
Carrying two copies of the major T allele is associated with typical levels of depressive symptoms and normal inflammatory markers. This genotype represents the most common genetic baseline globally.
What this genotype means: Typical baseline for depressive symptoms; Normal baseline levels of the inflammatory marker IL-6.
Gene function and biological role
Gene Function: The SLC6A4 gene encodes the serotonin transporter, a crucial protein responsible for recycling serotonin from the synaptic cleft back into neurons. By regulating the duration and intensity of serotonin signaling, this transporter plays a fundamental role in mood, anxiety, and emotional processing. It is also the primary therapeutic target for selective serotonin reuptake inhibitors, which are widely prescribed antidepressant medications. Variations within this gene can alter transporter expression levels and have been extensively studied in relation to stress resilience and psychiatric conditions.
Variant Impact: Situated in the 5 prime untranslated region of the SLC6A4 gene, rs6354 is a single nucleotide polymorphism that can influence gene expression and transporter availability. The G allele represents the minor variant, while the T allele is the more common major variant globally. Because of its location in a regulatory region, this variant is thought to modulate how efficiently the serotonin transporter protein is synthesized. Researchers have investigated this specific genetic change for its potential role in susceptibility to depressive symptoms and systemic inflammatory markers.
Key Insight: This genetic variant directly links emotional health with physical inflammation, demonstrating a shared biological pathway between mood regulation and the immune system.
Location: SLC6A4. Chromosome 17 · 17q11.2 · 30.2 Mb
Estimated prevalence by population
Global 5.1%; European 3.5%; African 10.0%; East Asian 1.3%; South Asian 3.2%; Americas 2.7%; Ashkenazi 2.8%; Finnish 3.3%; Middle Eastern 2.8%; Amish 0.9%.
Estimated GG genotype frequency.
Global 33.1%; European 30.5%; African 43.2%; East Asian 20.0%; South Asian 29.3%; Americas 27.7%; Ashkenazi 28.0%; Finnish 29.7%; Middle Eastern 27.8%; Amish 16.8%.
Estimated GT genotype frequency.
Global 61.8%; European 66.0%; African 46.8%; East Asian 78.7%; South Asian 67.6%; Americas 69.6%; Ashkenazi 69.2%; Finnish 66.9%; Middle Eastern 69.4%; Amish 82.4%.
Estimated TT genotype frequency.
Showing effects for G/G genotype
Neurology & Mental Health
Mood Disorders
Depressive Symptoms. Evidence: 3/10. Source: PMID 20031642. Increased Risk.
Immunity & Inflammation
Inflammatory & Circulating Protein Markers
Inflammation. Evidence: 3/10. Source: PMID 20031642. Higher IL-6 Levels.
Lifestyle, Fitness & Aging
Height & Body Size
Height. Evidence: 6/10. Source: PMID 36224396. Slightly Shorter.
Showing effects for G/T genotype
Height. Evidence: 6/10. Source: PMID 36224396. Typical.
Showing effects for T/T genotype
Depressive Symptoms. Evidence: 3/10. Source: PMID 20031642. Typical Risk.
Inflammation. Evidence: 3/10. Source: PMID 20031642. Typical IL-6 Levels.
Height. Evidence: 6/10. Source: PMID 36224396. Slightly Taller.
What this genotype means for the people who carry it
Sample genotype: GG (Homozygous)
Serotonin transporter regulation plays a critical role in managing mood and emotional stability. Research indicates that the minor G allele of this variant is significantly associated with higher scores on the Beck Depression Inventory. Furthermore, this genetic profile is linked to elevated plasma levels of interleukin-6, a key marker of systemic inflammation. This dual association suggests a shared biological pathway linking mood regulation and inflammatory responses. While these findings point to a higher vulnerability to depressive symptoms, they do not guarantee the development of any clinical disorder. Other studies have explored how these genetic variations relate to serotonin transporter availability in the brain. Understanding this genetic baseline can help individuals focus on proactive stress management and anti-inflammatory lifestyle choices.
Higher vulnerability to depressive symptoms; Elevated levels of the inflammatory marker IL-6.
Sample genotype: GT (Heterozygous)
Emotional health and inflammatory pathways are closely intertwined through the activity of the serotonin transporter. Studies show that individuals carrying at least one copy of the minor G allele tend to exhibit higher depressive symptom scores. This same genetic group also shows elevated levels of interleukin-6, indicating a potential increase in systemic inflammation. The correlation between these two factors suggests that serotonin pathway variations may influence both neural and immune systems. Although this genotype is linked to increased vulnerability, it represents a risk factor rather than a direct cause of depression. Brain imaging studies have also investigated how such variants affect the density of serotonin transporters in key mood-regulating regions. Maintaining a healthy lifestyle with regular exercise and stress-reduction techniques can help mitigate these genetic tendencies.
Increased susceptibility to depressive symptoms; Slightly elevated inflammatory markers.
Sample genotype: TT (Homozygous)
A typical genetic baseline for serotonin transporter function is characterized by the presence of two major T alleles. Research has shown that individuals with this genotype generally exhibit lower depressive symptom scores compared to those carrying the minor G allele. Additionally, this profile is associated with typical, non-elevated levels of the inflammatory marker interleukin-6. ClinVar assessments also classify the T allele as likely benign, indicating it does not pose an inherent risk for behavior disorders. While this genotype provides a stable baseline, overall emotional well-being remains heavily influenced by environmental factors and lifestyle. Some studies have also examined how this variant relates to the availability of serotonin transporters in the brain. Overall, this genetic makeup is considered highly favorable for maintaining typical mood regulation and inflammatory balance.
Typical baseline for depressive symptoms; Normal baseline levels of the inflammatory marker IL-6.
Variants with shared genetic architecture
rs2020942 · SLC6A4 Gene · Chr 17 · Body Fat and BMI
rs25531 · SLC6A4 Gene · Chr 17 · Stress and Mood Regulation
rs1042173 · SLC6A4 Gene · Chr 17 · Alcohol and Pain Sensitivity
Content updated August 2026.
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