What you carry at this position in your DNA and what research says about it.
Blood Pressure Risk: 8/10 evidence, 24 publications.
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Sample genotype (not yours): C/C
Higher Blood Pressure and Autoimmune Risk
Two copies of the C allele are linked to higher systolic and diastolic blood pressure. This genetic profile is also associated with an increased risk of autoimmune conditions and a poorer response to certain blood pressure medications.
What this genotype means: Higher systolic and diastolic blood pressure; Increased risk of hypertension; Elevated susceptibility to systemic sclerosis and lupus.
Sample genotype (not yours): A/A
Typical Blood Pressure and Lower Autoimmune Risk
Two copies of the protective A allele are linked to healthier blood pressure levels. This genetic profile is also associated with a typical risk of autoimmune conditions and a standard response to blood pressure medications.
What this genotype means: Typical, healthier blood pressure levels; Lower risk of developing hypertension; Standard risk of systemic sclerosis and lupus.
Sample genotype (not yours): C/A
Slightly Higher Blood Pressure and Autoimmune Risk
One copy of the C allele is associated with a modest increase in blood pressure. This genetic profile also slightly elevates the risk of certain autoimmune conditions and may reduce response to some water pills.
What this genotype means: Modestly higher blood pressure; Slightly increased risk of hypertension; Slightly elevated risk of systemic sclerosis and lupus.
Gene function and biological role
Gene Function: The CSK gene encodes the C-terminal Src kinase, an enzyme that plays a critical role in regulating cell growth, immune responses, and vascular tone [1]. By phosphorylating Src family kinases, CSK acts as a key off-switch for cellular signaling pathways that control blood vessel constriction [1] [2]. Proper regulation of this kinase is essential for maintaining normal blood pressure and preventing chronic vascular inflammation [2]. Variations in this gene can alter its expression levels, directly impacting how strongly arteries constrict in response to stress [2] [3].
Variant Impact: The rs1378942 variant is located within an intron of the CSK gene and acts as a major genetic regulator of blood pressure [1]. This genetic change influences the expression of the CSK enzyme, thereby modifying the body's natural control over blood vessel relaxation and tension [1] [2]. The C allele is widely recognized as the risk-increasing variant, consistently associated with higher systolic and diastolic blood pressure across diverse populations [1] [4]. Conversely, the A allele is associated with lower overall blood pressure and a reduced likelihood of developing hypertension [4] [5].
Key Insight: This variant not only influences everyday blood pressure but also interacts with dietary factors like fish oil intake, which may lower blood pressure more effectively in people with the protective A/A genotype.
Location: CSK. Chromosome 15 · 15q24.1 · 74.8 Mb
Estimated prevalence by population
Global 37.6%; European 11.8%; African 78.2%; East Asian 68.1%; South Asian 64.4%; Americas 41.2%; Ashkenazi 19.2%; Finnish 20.2%; Middle Eastern 20.8%; Amish 29.5%.
Estimated CC genotype frequency.
Global 37.9%; European 45.1%; African 20.5%; East Asian 28.8%; South Asian 31.7%; Americas 46.0%; Ashkenazi 49.2%; Finnish 49.5%; Middle Eastern 49.6%; Amish 49.6%.
Estimated CA genotype frequency.
Global 24.5%; European 43.1%; African 1.3%; East Asian 3.1%; South Asian 3.9%; Americas 12.8%; Ashkenazi 31.6%; Finnish 30.3%; Middle Eastern 29.6%; Amish 20.9%.
Estimated AA genotype frequency.
Showing effects for C/C genotype
Cardiovascular & Metabolic
Hypertension
Blood Pressure. Evidence: 8/10. Source: PMID 21909115. Higher Blood Pressure.
Heart Disease
Heart Disease. Evidence: 6/10. Source: PMID 30525989. Increased Risk.
Immunity & Inflammation
Autoimmune Diseases
Systemic Sclerosis. Evidence: 7/10. Source: PMID 31672989. Increased Risk.
Lupus. Evidence: 3/10. Source: PMID 28714469. Increased Risk.
Pharmacogenomics
Cardiovascular Drug Response
Diuretic Response. Evidence: 5/10. Source: PMID 31327267. Poorer Response.
Showing effects for A/A genotype
Blood Pressure. Evidence: 8/10. Source: PMID 21909115. Typical BP.
Heart Disease. Evidence: 6/10. Source: PMID 30525989. Typical Risk.
Systemic Sclerosis. Evidence: 7/10. Source: PMID 31672989. Typical Risk.
Lupus. Evidence: 3/10. Source: PMID 28714469. Typical Risk.
Diuretic Response. Evidence: 5/10. Source: PMID 31327267. Typical Response.
Showing effects for C/A genotype
Blood Pressure. Evidence: 8/10. Source: PMID 21909115. Slightly Higher BP.
Heart Disease. Evidence: 6/10. Source: PMID 30525989. Slightly Increased.
Systemic Sclerosis. Evidence: 7/10. Source: PMID 31672989. Slightly Increased.
Lupus. Evidence: 3/10. Source: PMID 28714469. Slightly Increased.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Two copies of the C allele predispose individuals to higher systolic and diastolic blood pressure measurements [1] [2]. Large-scale genetic studies show that this genotype is associated with higher baseline blood pressure levels [1] [2]. This genetic predisposition can elevate the overall risk of developing hypertension over time [3]. Additionally, this variant is linked to a higher susceptibility to autoimmune disorders such as systemic sclerosis and systemic lupus erythematosus [4] [5]. Research also suggests that individuals with this genotype may experience a less effective blood pressure-lowering response when prescribed thiazide diuretics like hydrochlorothiazide [6]. Managing cardiovascular health through lifestyle choices remains highly important for individuals with this genetic profile.
Higher systolic and diastolic blood pressure; Increased risk of hypertension; Elevated susceptibility to systemic sclerosis and lupus; Reduced response to hydrochlorothiazide medication.
Sample genotype: AA (Homozygous)
Two copies of the protective A allele are associated with lower average blood pressure [1]. Large-scale genetic analyses show that individuals with this genotype tend to have lower systolic and diastolic blood pressure compared to those carrying the C allele [1] [2]. This genetic profile provides natural protection against the development of hypertension [3]. Additionally, this genotype is associated with a typical, non-elevated risk for autoimmune disorders such as systemic sclerosis and systemic lupus erythematosus [4] [5]. When treating high blood pressure, individuals with this genotype are also more likely to experience a standard, favorable response to thiazide diuretics like hydrochlorothiazide [6]. This genetic baseline supports overall cardiovascular and immune health.
Typical, healthier blood pressure levels; Lower risk of developing hypertension; Standard risk of systemic sclerosis and lupus; Favorable response to hydrochlorothiazide medication.
Sample genotype: CA (Heterozygous)
A single copy of the C allele is associated with a modest increase in both systolic and diastolic blood pressure compared to the protective genotype [1] [2]. Over time, this slight elevation can contribute to a higher likelihood of developing hypertension [3]. This genotype also carries a moderately increased risk for autoimmune conditions like systemic sclerosis and lupus [4] [5]. Furthermore, clinical studies indicate that individuals with a C allele may have a slightly poorer response to hydrochlorothiazide, a common first-line blood pressure medication [6]. Maintaining a balanced diet and regular exercise can help mitigate these genetically influenced cardiovascular risks.
Modestly higher blood pressure; Slightly increased risk of hypertension; Slightly elevated risk of systemic sclerosis and lupus; Slightly reduced response to hydrochlorothiazide.
Variants with shared genetic architecture
rs1173771 · NPR3 Gene · Chr 5 · Blood Pressure Risk
rs1458038 · FGF5 Gene · Chr 4 · Blood Pressure
rs167479 · RGL3 Gene · Chr 19 · Blood Pressure Risk
Genetic variants in novel pathways influence blood pressure and cardiovascular disease risk.
Genome-wide association study identifies eight loci associated with blood pressure.
Transancestral mapping and genetic load in systemic lupus erythematosus.
Content updated August 2026.
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