What you carry at this position in your DNA and what research says about it.
Colorectal Cancer Risk: 7/10 evidence, 24 publications.
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Sample genotype (not yours): T/T
Elevated Colorectal Cancer Risk
Two copies of the T allele are associated with a significantly increased risk of colorectal cancer. This genetic profile represents the highest genetic risk at this specific locus.
What this genotype means: Approximately 1.70x higher risk of colorectal cancer; Elevated susceptibility to precancerous colorectal adenomas.
Sample genotype (not yours): C/C
Typical Colorectal Cancer Risk
Two copies of the common C allele are associated with average baseline risk for colorectal cancer. This genetic profile does not carry the elevated risk associated with the T variant.
What this genotype means: Typical baseline risk of colorectal cancer; No genetically elevated risk of colorectal adenomas.
Sample genotype (not yours): T/C
Moderately Increased Colorectal Cancer Risk
One copy of the T allele is associated with a moderately increased risk of colorectal cancer. This genetic profile represents a low-penetrance risk factor.
What this genotype means: Approximately 1.23x higher risk of colorectal cancer; Increased susceptibility to colorectal adenomas.
Gene function and biological role
Gene Function: The GREM1 gene encodes gremlin-1, a protein that plays a vital role in the bone morphogenetic protein signaling pathway. This pathway is crucial for regulating cell growth, differentiation, and tissue development in the colon. Alterations in GREM1 regulation can lead to uncontrolled cell proliferation and the formation of polyps. Research indicates that genetic variants in this region affect enhancers that modulate GREM1 expression [1]. This modulation is a key driver of susceptibility to colorectal tumors [2].
Variant Impact: The rs4779584 variant is an intergenic single nucleotide polymorphism located on chromosome 15q13.3 between the GREM1 and SCG5 genes. It acts as a regulatory variant, influencing the activity of genetic enhancers rather than changing a protein sequence directly [1]. The T allele of this variant is associated with an increased susceptibility to colorectal cancer [3]. Studies suggest this genetic risk is partly mediated through an increased likelihood of developing colorectal adenomas, which are precancerous polyps [4].
Key Insight: Inheriting risk variants at both this locus and rs6983267 can increase the overall risk of developing colorectal cancer by about three-fold.
Location: GREM1. Chromosome 15 · 15q13.3 · 32.7 Mb
Estimated prevalence by population
Global 14.2%; European 3.7%; African 30.6%; East Asian 65.0%; South Asian 16.6%; Americas 7.1%; Ashkenazi 1.6%; Finnish 8.1%; Middle Eastern 5.3%; Amish 0.8%.
Estimated TT genotype frequency.
Global 38.0%; European 31.2%; African 49.4%; East Asian 31.2%; South Asian 48.3%; Americas 39.1%; Ashkenazi 22.0%; Finnish 40.7%; Middle Eastern 35.6%; Amish 16.2%.
Estimated TC genotype frequency.
Global 47.8%; European 65.0%; African 20.0%; East Asian 3.7%; South Asian 35.2%; Americas 53.8%; Ashkenazi 76.4%; Finnish 51.2%; Middle Eastern 59.1%; Amish 83.0%.
Estimated CC genotype frequency.
Showing effects for T/T genotype
Cancer & Oncology
Colorectal Cancer
Colorectal Cancer. Evidence: 7/10. Source: PMID 18372905. ~1.7x Higher Risk.
Colorectal Adenoma. Evidence: 7/10. Source: PMID 22999960. Increased Risk.
GREM1 Expression. Evidence: 3/10. Source: PMID 33476087. Altered Expression.
Showing effects for C/C genotype
Colorectal Cancer. Evidence: 7/10. Source: PMID 18372905. Typical Risk.
Colorectal Adenoma. Evidence: 7/10. Source: PMID 22999960. Typical Risk.
GREM1 Expression. Evidence: 3/10. Source: PMID 33476087. Typical Expression.
Showing effects for T/C genotype
Colorectal Cancer. Evidence: 7/10. Source: PMID 18372905. ~1.2x Higher Risk.
What this genotype means for the people who carry it
Sample genotype: TT (Homozygous)
Possessing two copies of the T allele is associated with the highest level of genetic susceptibility at this locus. Studies show that the T/T genotype carries approximately a 1.70-fold increased risk of developing colorectal cancer compared to the typical C/C genotype [1]. This increased risk is often mediated through a higher likelihood of developing colorectal adenomas, which are precancerous polyps [2]. When combined with other risk variants, the cumulative impact on bowel cancer risk can be even more pronounced [1]. Despite the elevated risk, this is a low-penetrance variant, and lifestyle factors alongside standard screening play a major role in overall health outcomes.
Approximately 1.70x higher risk of colorectal cancer; Elevated susceptibility to precancerous colorectal adenomas.
Sample genotype: CC (Homozygous)
Inheriting two copies of the common C allele provides a typical baseline risk profile at this locus. Large-scale genome-wide association studies have established that this genotype is associated with average baseline risk of developing colorectal cancer [1]. Unlike carriers of the T variant, people with this genetic profile do not show elevated susceptibility to colorectal adenomas, which are precursor polyps that can become cancerous [2]. This baseline risk is consistent across multiple studied populations, including European and East Asian cohorts [3]. While having a typical genetic risk is favorable, standard screening guidelines still apply based on age and family history.
Typical baseline risk of colorectal cancer; No genetically elevated risk of colorectal adenomas.
Sample genotype: TC (Heterozygous)
Inheriting one copy of the T allele at this locus is linked to a moderate increase in colorectal cancer susceptibility. Research indicates that the T/C genotype carries approximately a 1.23-fold higher risk of developing colorectal cancer compared to the typical C/C genotype [1]. This genetic variant is thought to influence the risk of developing colorectal adenomas, which are precancerous polyps [2]. The association has been replicated across several large-scale genetic studies and meta-analyses [3]. While this represents an elevated risk, it is considered a low-penetrance factor, meaning it slightly nudges overall risk rather than guaranteeing disease development.
Approximately 1.23x higher risk of colorectal cancer; Increased susceptibility to colorectal adenomas.
Variants with shared genetic architecture
rs10411210 · RHPN2 Gene · Chr 19 · Colorectal Cancer Risk
rs10505477 · CASC8 Gene · Chr 8 · Cancer Susceptibility Risk
rs10774214 · CCND2-AS1 Gene · Chr 12 · Colorectal Cancer Risk
Meta-analysis of new genome-wide association studies of colorectal cancer risk.
Content updated August 2026.
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