What you carry at this position in your DNA and what research says about it.
C-Reactive Protein Levels: 9/10 evidence, 53 publications.
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Sample genotype (not yours): C/C
Typical Inflammation Levels and Typical Colorectal Cancer Risk
This genotype is associated with typical baseline levels of C-reactive protein, a marker of inflammation. Colorectal cancer risk is typical for this genotype.
What this genotype means: Typical baseline C-reactive protein levels; Typical risk of colorectal cancer; Lower risk of systemic lupus erythematosus.
Sample genotype (not yours): C/G
Lower Inflammation Levels and Reduced Colorectal Cancer Risk
This genotype is associated with lower baseline levels of C-reactive protein, which may help protect against chronic inflammation. Colorectal cancer risk is typical, with a slightly higher risk of lupus.
What this genotype means: Lower baseline C-reactive protein levels; Typical risk of colorectal cancer; Slightly increased risk of systemic lupus erythematosus.
Sample genotype (not yours): G/G
This genotype is associated with lower baseline levels of C-reactive protein, which may help protect against chronic inflammation. It is linked to a higher risk of colorectal cancer and a slightly higher risk of lupus.
What this genotype means: Lower baseline C-reactive protein levels; Increased risk of colorectal cancer; Slightly increased risk of systemic lupus erythematosus.
Gene function and biological role
Gene Function: The CRP gene encodes C-reactive protein, a key biomarker of systemic inflammation produced by the liver in response to inflammatory cytokines [1]. It plays an essential role in the innate immune system by binding to foreign pathogens and damaged cells to facilitate their clearance [2]. Circulating levels of this protein rise rapidly during acute infections, tissue injury, or chronic inflammatory states [1]. Genetic variations within this gene can significantly influence baseline levels of C-reactive protein in the bloodstream [3].
Variant Impact: The rs1800947 variant is a synonymous change in the CRP gene, meaning it does not alter the amino acid sequence of the C-reactive protein but can still affect its expression levels [4]. This genetic marker is strongly associated with baseline concentrations of C-reactive protein in the blood [1]. The major C allele is linked to typical or higher baseline levels of C-reactive protein, whereas the minor G allele is associated with lower baseline levels [1]. Additionally, this variant has been studied for its potential role in modifying susceptibility to chronic inflammatory conditions and certain cancers [5].
Key Insight: The minor G allele of this variant is associated with lower baseline C-reactive protein levels, which may offer protection against chronic inflammation-related conditions, but it also correlates with a slightly increased risk of systemic lupus erythematosus.
Location: CRP. Chromosome 1 · 1q23.2 · 159.7 Mb
Estimated prevalence by population
Global 91.3%; European 87.8%; African 98.0%; East Asian 87.1%; South Asian 95.6%; Americas 92.4%; Ashkenazi 84.1%; Finnish 89.0%; Middle Eastern 95.3%; Amish 87.7%.
Estimated CC genotype frequency.
Global 8.4%; European 11.8%; African 2.0%; East Asian 12.4%; South Asian 4.4%; Americas 7.5%; Ashkenazi 15.3%; Finnish 10.7%; Middle Eastern 4.6%; Amish 11.9%.
Estimated CG genotype frequency.
Global 0.3%; European 0.4%; African < 0.1%; East Asian 0.4%; South Asian 0.1%; Americas 0.2%; Ashkenazi 0.7%; Finnish 0.3%; Middle Eastern 0.1%; Amish 0.4%.
Estimated GG genotype frequency.
Showing effects for C/C genotype
Immunity & Inflammation
Inflammatory & Circulating Protein Markers
C-Reactive Protein. Evidence: 9/10. Source: PMID 30388399. Typical Levels.
Autoimmune Diseases
Lupus. Evidence: 4/10. Source: PMID 18793001. Typical Risk.
Cancer & Oncology
Colorectal Cancer
Colorectal Cancer. Evidence: 4/10. Source: PMID 24761881. Typical Risk.
Showing effects for C/G genotype
C-Reactive Protein. Evidence: 9/10. Source: PMID 30388399. Lower Levels.
Lupus. Evidence: 4/10. Source: PMID 18793001. Increased Risk.
Showing effects for G/G genotype
Colorectal Cancer. Evidence: 4/10. Source: PMID 24761881. Increased Risk.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Baseline levels of C-reactive protein (CRP) tend to be typical or slightly higher in those with two copies of the major C allele [1]. CRP serves as a primary biomarker of systemic inflammation in the body [1]. While these levels are considered normal, they do not offer the reduced inflammation seen in G allele carriers [2]. Colorectal cancer risk for this common genotype is typical, and it is the reference group against which the rare G/G genotype shows elevated risk [3]. Conversely, this genotype is associated with a lower risk of developing systemic lupus erythematosus [4]. This protective effect against autoimmunity is thought to occur because typical CRP levels facilitate the proper clearance of cellular debris [4].
Typical baseline C-reactive protein levels; Typical risk of colorectal cancer; Lower risk of systemic lupus erythematosus.
Sample genotype: CG (Heterozygous)
Baseline levels of C-reactive protein (CRP) are significantly lower in those with one copy of the minor G allele [1]. Because CRP is a primary biomarker of systemic inflammation, lower baseline levels are generally considered favorable for long-term health [2]. Colorectal cancer risk for heterozygotes is typical: the source meta-analysis found no association for this genotype [3]. However, there is a complex biological trade-off. Lower baseline CRP levels have also been linked to a slightly increased susceptibility to systemic lupus erythematosus, an autoimmune disease [4]. This is because CRP plays a protective role in clearing cellular debris, and lower levels may lead to an accumulation of self-antigens that trigger autoimmunity [4].
Lower baseline C-reactive protein levels; Typical risk of colorectal cancer; Slightly increased risk of systemic lupus erythematosus.
Sample genotype: GG (Homozygous)
Baseline levels of C-reactive protein (CRP) are significantly lower in those with two copies of the minor G allele [1]. Because CRP is a primary biomarker of systemic inflammation, lower baseline levels are generally considered favorable for long-term health [2]. This rare genotype is the one the source meta-analysis links to an increased risk of colorectal cancer, roughly 2.9-fold versus the common genotype [3]. However, there is a complex biological trade-off. Lower baseline CRP levels have also been linked to a slightly increased susceptibility to systemic lupus erythematosus, an autoimmune disease [4]. This is because CRP plays a protective role in clearing cellular debris, and lower levels may lead to an accumulation of self-antigens that trigger autoimmunity [4].
Lower baseline C-reactive protein levels; Increased risk of colorectal cancer; Slightly increased risk of systemic lupus erythematosus.
Variants with shared genetic architecture
rs3091244 · CRP Gene · Chr 1 · Inflammation and Aneurysm Risk
rs7553007 · CRP Gene · Chr 1 · C-Reactive Protein Levels
rs1205 · CRP Gene · Chr 1 · C-Reactive Protein Levels
Content updated August 2026.
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