The ABCG5 gene helps move plant based fats called sterols, along with some cholesterol, out of the body through the intestine and liver. If it does not work properly, these fats can build up in the blood and tissues and cause sitosterolemia, which may lead to tendon lumps, early artery disease, or changes in blood cells. This gene plays an important role in keeping sterol levels balanced. Most people hear about it during testing for unexplained high cholesterol.
What is a gene?
Genes are stretches of DNA that give cells instructions to make molecules or regulate processes in the body. Some genes provide the directions for producing proteins, the parts of cells that do much of the work. Others mostly control when certain processes happen, where they happen, and how active they are. Taken together, genes affect how the body grows and works, and they can influence how you respond to food, stress, or medicines. More detail is available in the LearnHub.
Overview
ABCG5Gene function
What if the gene works
The ABCG5 gene helps move plant sterols and some cholesterol out of the body. It supports healthy balance by limiting absorption from food and aiding release into bile.
Risk
What if the gene does not work
Variants in the ABCG5 gene can cause sitosterolemia, where the body absorbs too much plant sterol and may build up cholesterol. Effects range from mild to more severe and can include tendon xanthomas and earlier heart or blood vessel disease.
Treatment
What does that mean for your treatment
A pathogenic variant in the ABCG5 gene can make treatment more focused on lowering plant sterol absorption. Ezetimibe is a well established first line medicine because it reduces uptake of plant sterols and cholesterol, and care also includes a diet low in plant sterols and cholesterol. Bile acid sequestrants may help in some people, while statins alone are often less effective for the core problem.
Conditions associated with ABCG5
Gene function
What if the gene works
ABCG5 helps your body handle sterols, a group of fats that includes cholesterol and plant sterols from food. It is most active in the small intestine and liver, where it works with the ABCG8 gene as a transport pair. Together, they keep sterol movement more controlled from one step to the next.
In the small intestine, the ABCG5 gene works with the ABCG8 gene to send some plant sterols and cholesterol back into the gut. This helps control how much cholesterol and plant sterols your body absorbs from food.
In the liver, the ABCG5 gene helps move cholesterol and plant sterols into bile, a digestive fluid that carries them toward the intestine. This supports one of the body's usual ways to remove extra sterols.
By limiting absorption and supporting removal, the ABCG5 gene helps keep sterol levels balanced. This steady control is part of how your body manages cholesterol and plant sterols day to day.
What is a variant?
A genetic variant is a minor change in the DNA sequence of a gene. These changes are common and help shape normal human diversity, including differences in appearance, metabolism, and the way the body responds to environmental influences. Many variants do not have any noticeable effect and simply represent natural genetic variation. In some cases, though, a variant can change how a gene functions more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Many variants in the ABCG5 gene make its transporter protein unstable, shortened, or unable to pair properly with the ABCG8 gene protein, so less plant sterol is moved out of gut and liver cells. In practical terms, variants in the ABCG5 gene can reduce plant sterol transport to different degrees. Milder variants may leave some activity, while more severe variants can cause little or none and are often linked to earlier or more noticeable sitosterolemia.
How variants are linked to conditions
Pathogenic variants in the ABCG5 gene can cause sitosterolemia, a rare inherited condition in which plant sterols build up in the body and cholesterol may also be high. ABCG5 gene variants linked to sitosterolemia are a well-established finding, especially when both copies of the gene are affected. Some ABCG5 variants have also been associated with a higher chance of gallstones and differences in cholesterol levels, but these links do not guarantee that a person will develop those problems.
A variant is not necessarily a diagnosis
Genetic variants are a normal feature of human biology, and they are common throughout the general population. Most do not have a direct effect on health and instead reflect natural human variation. For many genes, having a variant associated with a condition suggests a possible link rather than a definite diagnosis, especially when several genes and environmental factors are involved. In some situations, though, a single well-characterized variant in a particular gene can be enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For ABCG5, risk is mainly determined by whether someone inherits harmful changes in both copies of the gene, which can cause sitosterolemia. In people living with this condition, foods high in plant sterols, such as some vegetable oils, nuts, seeds, and fortified products, can raise blood sterol levels and make problems more likely.
Inheritance of ABCG5 variants
ABCG5-related sitosterolemia follows an autosomal recessive inheritance pattern. This means a person usually inherits one ABCG5 gene variant from each parent before developing the condition. Parents who each carry one variant are often unaffected carriers, and with each pregnancy there is a 25% chance their child will inherit both variants, a 50% chance the child will be a carrier, and a 25% chance the child will inherit neither variant. In practical terms, the ABCG5 inheritance pattern often appears in siblings rather than passing directly from an affected parent to every child.
What does my ABCG5 result mean for my family?
For ABCG5, family implications are usually tied to a recessive condition called sitosterolemia. This often means parents of an affected child are healthy carriers, and brothers or sisters may also have the condition or be carriers. Other close relatives may carry the same gene change, especially on the same side of the family. Because of this, family members may wish to discuss whether the result is relevant to them.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the ABCG5 gene, a lab can analyze DNA from a blood sample, saliva, or cheek swab. Genetic testing for ABCG5 variants looks for changes in the gene's code and may report whether a variant is disease causing, likely benign, or uncertain.
When should I consider getting a genetic test?
Consider testing if you or your child has very high cholesterol from a young age, fatty lumps on tendons, or early heart disease, especially if plant sterol levels are high or close relatives have similar findings. Testing for ABCG5 can help confirm sitosterolemia, an inherited condition that can guide treatment and family screening.
A genetic result is only one part of your health story
A genetic result can provide useful insight, but how much it can tell you depends on the condition and the type of variant. Over time, many factors, including lifestyle, environment, age, and medical history, also shape how the body works. For some conditions, especially those affected by many genes, genetic information provides context rather than certainty and is best considered together with other parts of care. In other situations, a genetic result can offer a clear answer. In areas like medication response, genetic results can also help put individual experiences in context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Small differences in the body’s built in instructions can change how a drug is absorbed, broken down, moved through the body, or how strongly it acts at its target. This is common and helps explain why the same medication works well for one person, seems weaker in another, or causes more side effects in someone else. Medication response also depends on age, other health conditions, and other medicines, so genes are one part of the picture.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences affect the way people respond to medicines. It studies links between genes and drugs to help explain why the same treatment can work differently from one person to another. For many medicines, genes influence both how the body processes a drug and how strong its effects are. This information can support more informed and more individualized treatment decisions. You can read more about this topic in LearnHub.
Drugs influenced by the ABCG5 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication choices, so concerns about medicines, side effects, or how well treatment is working are best discussed with your doctor. ABCG5 has been studied for possible links to how some people respond to cholesterol-lowering medicines, but this is not used routinely to guide care.
History
ABCG5 entered medical genetics through the study of sitosterolemia, a rare inherited condition in which plant sterols build up in the body. In 2001, researchers identified the ABCG5 gene and the nearby ABCG8 gene as the key genes linked to this condition, helping explain a long-standing clinical puzzle. Building on this early work, scientists showed that these two genes were inherited together in families affected by sitosterolemia. That discovery marked an important step in understanding inherited cholesterol and sterol handling. Over time, descriptions became more precise as genetic testing made it easier to confirm the diagnosis. Today, ABCG5 is best known from that discovery pathway, which connected careful family studies with modern gene mapping.