What you carry at this position in your DNA and what research says about it.
Gallstone Risk: 10/10 evidence, 21 publications.
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Sample genotype (not yours): C/C
Lower Gallstone Risk
Bile cholesterol levels remain low, significantly reducing the likelihood of crystal and stone formation. However, blood cholesterol and cardiovascular risks are slightly elevated.
What this genotype means: Significantly lower risk of cholesterol gallstones; Slightly higher circulating LDL and total cholesterol.
Sample genotype (not yours): C/T
Moderately Increased Gallstone Risk
A moderate amount of cholesterol is secreted into the bile, slightly raising the risk of gallstones while keeping blood lipids near the average range.
What this genotype means: Moderately elevated risk of gallstone formation; Typical blood cholesterol and cardiovascular risk profile.
Sample genotype (not yours): T/T
Higher Gallstone Risk
Highly active cholesterol excretion into the gallbladder increases the risk of gallstones, though blood cholesterol levels are naturally lower.
What this genotype means: Higher risk of developing cholesterol gallstones; Naturally lower circulating LDL and total cholesterol levels.
Gene function and biological role
Gene Function: The ABCG8 gene encodes sterolin-2, which partners with sterolin-1 to form a functional transporter in the liver and intestines [1]. This transporter pumps cholesterol and plant-derived sterols out of the body, directing them into the bile for excretion or preventing their absorption in the gut [1]. Highly active transporters lower blood cholesterol levels but saturate the gallbladder with excess cholesterol [2]. Conversely, lower transporter activity keeps cholesterol in circulation but protects the gallbladder from stone formation [2].
Variant Impact: The rs4245791 variant is an intronic change in the ABCG8 gene that influences how much of the transporter is produced in the liver [1]. The major T allele is associated with altered transporter expression, leading to higher cholesterol secretion into the bile [1]. This process lowers circulating blood lipids but increases the concentration of cholesterol in the gallbladder [2]. The minor C allele has the opposite effect, keeping more cholesterol in the bloodstream while keeping bile clear [2].
Key Insight: This genetic variant presents a direct biological trade-off where the allele that protects you from high cholesterol actually increases your risk of developing gallstones.
Location: ABCG8. Chromosome 2 · 2p21 · 43.8 Mb
Estimated prevalence by population
Global 6.4%; European 10.2%; African 1.7%; East Asian < 0.1%; South Asian 5.3%; Americas 5.4%; Ashkenazi 7.3%; Finnish 4.3%; Middle Eastern 11.3%; Amish 12.7%.
Estimated CC genotype frequency.
Global 34.5%; European 43.4%; African 22.8%; East Asian 1.2%; South Asian 35.5%; Americas 35.7%; Ashkenazi 39.4%; Finnish 33.0%; Middle Eastern 44.7%; Amish 45.9%.
Estimated CT genotype frequency.
Global 59.1%; European 46.4%; African 75.4%; East Asian 98.8%; South Asian 59.1%; Americas 58.9%; Ashkenazi 53.3%; Finnish 62.6%; Middle Eastern 44.0%; Amish 41.4%.
Estimated TT genotype frequency.
Showing effects for C/C genotype
Organ Systems
Digestive & Gut Disorders
Gallstones. Evidence: 6/10. Source: PMID 27094239. Lower Risk.
Cardiovascular & Metabolic
Heart Disease
Coronary Artery Disease. Evidence: 8/10. Source: PMID 36474045. ~1.1x Risk.
Lipids & Cholesterol
Total Cholesterol. Evidence: 10/10. Source: PMID 36220816. Slightly Higher.
LDL Cholesterol. Evidence: 10/10. Source: PMID 34887591. Slightly Higher.
Showing effects for C/T genotype
Gallstones. Evidence: 6/10. Source: PMID 27094239. ~1.14x Risk.
Coronary Artery Disease. Evidence: 8/10. Source: PMID 36474045. ~1.05x Risk.
Total Cholesterol. Evidence: 10/10. Source: PMID 36220816. Typical.
LDL Cholesterol. Evidence: 10/10. Source: PMID 34887591. Typical.
Showing effects for T/T genotype
Gallstones. Evidence: 6/10. Source: PMID 27094239. ~1.28x Risk.
Coronary Artery Disease. Evidence: 8/10. Source: PMID 36474045. Typical Risk.
Total Cholesterol. Evidence: 10/10. Source: PMID 36220816. Slightly Lower.
LDL Cholesterol. Evidence: 10/10. Source: PMID 34887591. Slightly Lower.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Reduced transporter activity limits the amount of cholesterol pumped into the gallbladder, keeping the bile fluid thin and free of crystals [1]. Large-scale genetic studies show this protective effect translates to a significantly lower risk of developing painful gallstones [1]. On the other hand, because less cholesterol is excreted, slightly more remains in the bloodstream [2]. This results in a modest increase in total and LDL cholesterol levels, which is associated with a minor increase in long-term cardiovascular risk [2]. Maintaining a heart-healthy diet can easily offset this mild blood lipid elevation.
Significantly lower risk of cholesterol gallstones; Slightly higher circulating LDL and total cholesterol.
Sample genotype: CT (Heterozygous)
Balanced transporter expression leads to intermediate levels of cholesterol excretion into both the bile and the bloodstream [1]. This intermediate state carries a moderate, step-wise increase in gallstone risk compared to the protective genotype [1]. Circulating blood lipids like LDL and total cholesterol remain very close to population averages [2]. While the genetic influence here is moderate, lifestyle factors play a major role in determining actual gallbladder outcomes [1]. Staying hydrated and consuming a fiber-rich diet can help maintain healthy bile flow.
Moderately elevated risk of gallstone formation; Typical blood cholesterol and cardiovascular risk profile.
Sample genotype: TT (Homozygous)
Elevated transporter activity efficiently clears cholesterol from the liver and bloodstream, dumping it directly into the bile [1]. While this process naturally lowers circulating LDL and total cholesterol, it supersaturates the gallbladder [1]. When bile becomes overloaded with cholesterol, the excess crystallizes and can eventually form solid gallstones [2]. Studies indicate a notable increase in lifetime gallstone risk for this profile [2]. Conversely, the efficient clearance of blood lipids provides a small, protective benefit against coronary artery disease [1].
Higher risk of developing cholesterol gallstones; Naturally lower circulating LDL and total cholesterol levels.
Variants with shared genetic architecture
rs11887534 · ABCG8 Gene · Chr 2 · Gallstone Risk
rs4299376 · ABCG8 Gene · Chr 2 · Heart and Gallstone Risk
rs6544713 · ABCG8 Gene · Chr 2 · Heart Disease Risk
Genetic regulation of serum phytosterol levels and risk of coronary artery disease.
Whole genome sequence analysis of blood lipid levels in >66,000 individuals.
Content updated August 2026.
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