What you carry at this position in your DNA and what research says about it.
Blood Pressure Regulation: 10/10 evidence, 20 publications.
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Sample genotype (not yours): C/C
Typical Blood Pressure and Normal Enzyme Levels
This genotype is associated with standard levels of dopamine beta-hydroxylase activity. It represents the baseline genetic profile for blood pressure regulation in most populations.
What this genotype means: Typical blood pressure baseline; Standard DBH enzyme activity; Lower risk of inflammatory bowel disease.
Sample genotype (not yours): C/T
Lower Blood Pressure and Reduced Enzyme Activity
Carrying one copy of the T allele is linked to lower blood pressure and reduced dopamine beta-hydroxylase levels. This provides a natural cardiovascular advantage but may slightly alter inflammatory responses.
What this genotype means: Lower average blood pressure; Reduced risk of hypertension; Slightly increased risk of inflammatory bowel disease.
Sample genotype (not yours): T/T
Lowest Blood Pressure and Significantly Reduced Enzyme Activity
Carrying two copies of the T allele is associated with the lowest blood pressure levels and significantly reduced enzyme activity. This genotype offers strong protection against hypertension but increases the risk of inflammatory bowel disease.
What this genotype means: Lowest average blood pressure; Strong protection against hypertension; Increased risk of inflammatory bowel disease.
Gene function and biological role
Gene Function: The DBH gene provides instructions for making dopamine beta-hydroxylase, an enzyme crucial for chemical signaling in the nervous system [1]. This enzyme converts dopamine, a neurotransmitter associated with reward and motivation, into norepinephrine, which regulates the body's stress response and blood pressure [1]. Produced primarily in specialized nerve cells and the adrenal glands, the enzyme is released into the bloodstream alongside neurotransmitters [2]. Variations in this gene can significantly alter the amount or activity of the circulating enzyme, directly impacting cardiovascular regulation and neurological function [2].
Variant Impact: The rs6271 variant is a missense mutation in the DBH gene that changes the amino acid arginine to cysteine at position 549 of the protein [2]. This structural alteration impairs the normal secretion of the dopamine beta-hydroxylase enzyme from cells and reduces its overall activity [2]. Because the enzyme is responsible for synthesizing norepinephrine, this reduction alters the balance of catecholamines in the body [1]. Consequently, this single nucleotide change has a cascading effect on systemic blood pressure and vascular tone [1].
Key Insight: The T allele acts as a natural blood pressure dampener by reducing the conversion of dopamine to norepinephrine.
Location: DBH. Chromosome 9 · 9q34.2 · 133.7 Mb
Estimated prevalence by population
Global 90.8%; European 86.5%; African 97.3%; East Asian 99.9%; South Asian 98.4%; Americas 90.4%; Ashkenazi 87.9%; Finnish 87.1%; Middle Eastern 88.8%; Amish 92.0%.
Estimated CC genotype frequency.
Global 8.9%; European 13.0%; African 2.7%; East Asian 0.1%; South Asian 1.6%; Americas 9.3%; Ashkenazi 11.7%; Finnish 12.4%; Middle Eastern 10.9%; Amish 7.8%.
Estimated CT genotype frequency.
Global 0.3%; European 0.5%; African < 0.1%; East Asian < 0.1%; South Asian < 0.1%; Americas 0.2%; Ashkenazi 0.4%; Finnish 0.4%; Middle Eastern 0.3%; Amish 0.2%.
Estimated TT genotype frequency.
Showing effects for C/C genotype
Cardiovascular & Metabolic
Hypertension
Blood Pressure. Evidence: 10/10. Source: PMID 27618452. Typical.
Hypertension. Evidence: 10/10. Source: PMID 38965376. Typical Risk.
Pharmacogenomics
Drug Metabolism Enzyme Activity
DBH Enzyme Activity. Evidence: 3/10. Source: PMID 16616730. Typical Levels.
Immunity & Inflammation
Chronic Inflammatory Diseases
Inflammatory Bowel Disease. Evidence: 3/10. Source: PMID 30817802. Lower Risk.
Showing effects for C/T genotype
Blood Pressure. Evidence: 10/10. Source: PMID 27618452. Lower Blood Pressure.
Hypertension. Evidence: 10/10. Source: PMID 38965376. Lower Risk.
DBH Enzyme Activity. Evidence: 3/10. Source: PMID 16616730. Reduced Levels.
Inflammatory Bowel Disease. Evidence: 3/10. Source: PMID 30817802. Increased Risk.
Showing effects for T/T genotype
Blood Pressure. Evidence: 10/10. Source: PMID 27618452. Lowest Blood Pressure.
Hypertension. Evidence: 10/10. Source: PMID 38965376. Lowest Risk.
DBH Enzyme Activity. Evidence: 3/10. Source: PMID 16616730. Significantly Reduced.
Inflammatory Bowel Disease. Evidence: 3/10. Source: PMID 30817802. Highest Risk.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Having two copies of the C allele is the most common genetic profile globally, representing the standard baseline for dopamine beta-hydroxylase expression [1]. This genotype maintains typical enzyme activity, ensuring normal conversion of dopamine to norepinephrine under standard conditions [1]. However, large-scale genetic studies show that this baseline profile is associated with slightly higher systolic and diastolic blood pressure compared to carrying the T allele [2]. This elevation translates to a typical, yet relatively higher, risk of developing hypertension over time [3]. Conversely, this standard level of enzyme activity appears protective against certain inflammatory conditions, showing a significantly lower risk of inflammatory bowel disease compared to T allele carriers [4]. Individuals with this profile typically respond normally to standard cardiovascular medications if treatment is ever required [5]. Overall, this genetic makeup represents the standard physiological template for catecholamine metabolism in the general population [1].
Typical blood pressure baseline; Standard DBH enzyme activity; Lower risk of inflammatory bowel disease.
Sample genotype: CT (Heterozygous)
Carrying one copy of the T allele leads to a moderate reduction in circulating dopamine beta-hydroxylase levels due to altered protein secretion [1]. This reduction in enzyme activity limits the conversion of dopamine to norepinephrine, resulting in lower systemic vascular resistance [1]. Large genome-wide association studies confirm that this genetic profile is associated with lower systolic and diastolic blood pressure [2]. This reduction in blood pressure provides a protective effect against hypertension and associated cardiovascular strain [3]. However, this lower enzyme activity is also linked to an increased susceptibility to inflammatory bowel disease, representing a biological trade-off [4]. The lower baseline blood pressure may also influence how the body responds to physical stress or certain medications [5]. Despite this trade-off, the cardiovascular benefits of carrying a single T allele are well-documented across diverse populations [2].
Lower average blood pressure; Reduced risk of hypertension; Slightly increased risk of inflammatory bowel disease.
Sample genotype: TT (Homozygous)
Carrying two copies of the T allele results in the most pronounced reduction of dopamine beta-hydroxylase activity and secretion [1]. With significantly less enzyme available to synthesize norepinephrine, sympathetic nervous system tone is naturally dampened [1]. This physiological state is strongly associated with lower systolic and diastolic blood pressure measurements in large population cohorts [2]. The resulting cardiovascular profile offers robust protection against hypertension and long-term blood pressure-related organ damage [3]. However, the marked reduction in circulating enzyme levels is also associated with the highest risk of developing inflammatory bowel disease [4]. This genotype is relatively rare in most populations, making its physiological effects highly distinct [1]. Individuals with this profile may have a unique catecholamine balance that influences both cardiovascular and inflammatory pathways simultaneously [4].
Lowest average blood pressure; Strong protection against hypertension; Increased risk of inflammatory bowel disease.
Variants with shared genetic architecture
rs1611115 · DBH Gene · Chr 9 · Impulsivity and ADHD Risk
rs10857147 · FGF5 Gene · Chr 4 · Blood Pressure
rs11191580 · NT5C2 Gene · Chr 10 · Blood Pressure and Brain
Genome-wide association study of medication-use and associated disease in the UK Biobank.
Content updated August 2026.
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