The ABCG8 gene helps control how much cholesterol and plant sterols, which are cholesterol-like fats from foods, your body absorbs and gets rid of. What this gene does can influence how your body handles fats from meals. If it does not work properly, these fats can build up in the blood and tissues. Some people with harmful variants in the ABCG8 gene develop sitosterolemia, which can cause very high cholesterol, fatty bumps on the skin or tendons, and a higher chance of early heart and blood vessel disease.
What is a gene?
Genes are pieces of DNA that carry instructions your cells use to make molecules or regulate what happens in the body. Some provide the directions for producing proteins, which do much of the cell’s work. Others mainly control when certain processes take place, where they occur, and how active they are. Together, genes affect how the body develops and works, and they can also influence how you respond to food, stress, and medications. More detailed information on this topic is available in the LearnHub.
Overview
ABCG8Gene function
What if the gene works
The ABCG8 gene helps move cholesterol and plant sterols out of the liver and intestine. Working with the ABCG5 gene, it limits how much of these sterols your body keeps and supports normal cholesterol balance.
Risk
What if the gene does not work
More severe variants in the ABCG8 gene, usually affecting both copies, can cause sitosterolemia, with very high plant sterol levels, tendon lumps, blood changes, and early heart or blood vessel disease. Milder variants may mainly increase cholesterol gallstone risk.
Treatment
What does that mean for your treatment
Pathogenic variants in the ABCG8 gene can make treatment focus on lowering plant sterol absorption. Ezetimibe is a standard drug choice because it can reduce sterol uptake, and care is usually paired with a diet low in plant sterols and often cholesterol. Statins alone are often less helpful.
Conditions associated with ABCG8
Gene function
What if the gene works
Your body constantly sorts fats that come in from food and sends excess amounts back out. The ABCG8 gene supports this routine cleanup by helping handle cholesterol and plant sterols, substances from foods that resemble cholesterol. It works most closely with the ABCG5 gene in cells lining the small intestine and in the liver.
The ABCG8 gene helps make a transport protein that works with the ABCG5 gene. Together, they move cholesterol and plant sterols across cell membranes so extra amounts can be directed out of the cell.
In the small intestine, this transporter sends some sterols back into the gut after food is absorbed. That limits how much cholesterol and plant sterols the body keeps from a meal.
In the liver, it helps place sterols into bile, a digestive fluid that carries them toward the intestine. This is a key part of how the ABCG8 gene helps remove cholesterol from the body.
What is a variant?
A genetic variant is a small difference in the DNA sequence of a gene. These changes are common and help make up normal human diversity, such as differences in appearance, metabolism, or how the body responds to environmental influences. Many variants have no noticeable effect and simply represent natural genetic variation. In some situations, however, a variant can more significantly change how a gene functions and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the ABCG8 gene can alter how the transporter is folded, moved to the cell surface, or paired with the ABCG5 protein. In ABCG8 gene variants and sterol transport, milder missense variants may partly reduce export activity, while more severe variants, including truncating changes, can greatly reduce or abolish it. This can leave more plant sterols and cholesterol inside intestinal and liver cells and, in some cases, lead to earlier or more marked sitosterolemia.
How variants are linked to conditions
Pathogenic variants in both copies of the ABCG8 gene can cause sitosterolemia, a rare inherited condition marked by very high plant sterol levels and early cholesterol buildup. Common ABCG8 variants are also linked to a higher risk of cholesterol gallstones, so ABCG8 gene variants linked to gallstones and sitosterolemia are the best established clinical associations. Some changes may also modestly influence blood lipid results.
A variant is not necessarily a diagnosis
Genetic variants are a common and normal part of being human. Most do not directly affect health and simply reflect natural variation across people. In many genes, having a variant associated with a condition points to a possible link rather than a firm diagnosis, particularly when several genes and environmental influences play a role. In some situations, though, one well-characterized variant in a particular gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
Some ABCG8 changes can raise the chance of cholesterol gallstones, and that risk may be higher with obesity, rapid weight loss, a high-cholesterol diet, older age, and female sex. Rare harmful changes in both copies of ABCG8 can cause sitosterolemia, where eating a lot of plant sterols can worsen the condition.
Inheritance of ABCG8 variants
For families asking about the ABCG8 inheritance pattern, disease causing variants in the ABCG8 gene are best known to follow an autosomal recessive pattern in sitosterolemia. This means a person usually inherits one altered copy from each parent, and parents who each carry one variant are often healthy themselves. When both parents are carriers, each child has a 25% chance of inheriting both altered copies, a 50% chance of being a carrier, and a 25% chance of inheriting neither altered copy.
What does my ABCG8 result mean for my family?
For ABCG8, the best-known family pattern is linked to sitosterolemia, a rare inherited condition that affects how the body handles plant sterols and cholesterol. In families with this kind of result, brothers and sisters may also have the condition or be carriers, and parents are often carriers even if they have no symptoms. Children of someone with two changed ABCG8 copies will usually be carriers, and they could be affected if the other parent also carries a changed copy.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the ABCG8 gene, a lab can analyze DNA from a blood or saliva sample with genetic testing for ABCG8 variants, often as part of a sitosterolemia panel. Results may show a harmless change or a variant linked to sitosterolemia and are read alongside symptoms and cholesterol tests.
When should I consider getting a genetic test?
Genetic testing for the ABCG8 gene may be worth considering if you or your child has very high cholesterol from a young age, tendon lumps, or unusually high plant sterol levels, especially if close relatives have similar findings. It can help confirm a rare inherited condition called sitosterolemia and guide family testing.
A genetic result is only one part of your health story
A genetic result can be very informative, but how much it reveals depends on the condition and on the specific variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, also shape how the body functions. In some conditions, especially those influenced by many genes, genetic information provides context rather than certainty and is best considered alongside other parts of care. In other situations, a genetic result may offer a clear answer. In areas like medication response, genetic results can also help put individual experiences into perspective.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Two people can take the same treatment at the same dose, yet one may get better benefit while the other may notice less effect or more side effects. Part of the reason is that inherited differences can change how the body absorbs, breaks down, moves, or responds to a drug, and these differences are common.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in genes can affect the way a person responds to medications. It looks at connections between genes and drugs to better understand why the same treatment may work differently from one person to another. For many medicines, genes can influence how strongly a drug works or how the body handles it. This information can support more informed, more individualized treatment decisions. More on this topic is available in the LearnHub.
Drugs influenced by the ABCG8 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication choices, so general questions about your health, symptoms, or medicines are best discussed with your doctor.
History
The story of the ABCG8 gene began with a rare inherited condition called sitosterolemia, first described in the 1970s when doctors noticed unusually high plant sterol levels in some families. Building on this early work, scientists uncovered more about the gene. Around 2000, researchers identified variants in the ABCG8 gene and the nearby ABCG5 gene as the cause, marking an important step in understanding how the body handles sterols from food. This discovery helped explain why some people absorb and retain these substances differently from others. Although the ABCG8 gene has not entered the public spotlight in the way some genes have, its discovery became a key milestone in cholesterol and lipid research.