The ABCB11 gene gives liver cells instructions for a pump that moves bile salts into bile, which helps your body digest fats and clear waste. This gene plays an important role in keeping bile flowing, and when it does not work well, bile can build up in the liver. That can lead to jaundice, intense itching, gallstones, or liver damage. Pathogenic variants in the ABCB11 gene are linked to inherited bile flow conditions, including progressive familial intrahepatic cholestasis type 2, and to some cases of cholestasis during pregnancy.
What is a gene?
Genes are stretches of DNA that hold instructions your cells use to make molecules or regulate activities in the body. Some provide the code for proteins, which are the parts of cells that do much of the work. Others mostly guide 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 your response to food, stress, and medicines. For a deeper look at this topic, visit the LearnHub.
Overview
ABCB11Gene function
What if the gene works
The ABCB11 gene helps liver cells move bile acids into bile. This supports bile flow, helps digest fats, and limits bile acid buildup in the liver.
Risk
What if the gene does not work
Variants in the ABCB11 gene can reduce bile flow from the liver, causing cholestasis. Milder variants may lead to itching or cholestasis during pregnancy, while more severe variants often cause childhood liver disease and, in some cases, progressive liver damage.
Treatment
What does that mean for your treatment
Pathogenic variants in the ABCB11 gene can influence treatment because people with some remaining bile pump activity may improve with ursodeoxycholic acid, while severe loss-of-function variants are less likely to. Care may then focus on bile acid lowering treatment, including odevixibat in eligible people, and some may need biliary diversion or liver transplant.
Conditions associated with ABCB11
Gene function
What if the gene works
Your liver depends on the ABCB11 gene to move bile salts into bile, the digestive fluid that travels from the liver to the gut. This is a key part of how the ABCB11 gene supports bile flow and digestion. By keeping this process steady, it helps your body handle fats from food in a controlled way.
Inside liver cells, the ABCB11 gene provides instructions for a transport protein that uses energy to push bile salts into tiny bile channels. This step is central to making bile and moving it in the right direction.
Bile salts are a major force that draws fluid into bile. By sending these salts into bile, this gene helps keep bile flowing from the liver toward the gallbladder and small intestine.
Once bile reaches the small intestine, bile salts help break up fats into small droplets. This makes it easier for your body to digest fats and absorb vitamins A, D, E, and K.
The ABCB11 protein helps keep bile salts moving out of liver cells as part of their normal handling and recycling. This supports the liver’s day to day work processing nutrients and substances headed for removal in bile.
What is a variant?
A genetic variant is a slight difference in the DNA sequence within a gene. These differences are common and are part of normal human diversity, including differences in appearance, metabolism, and the way the body reacts to environmental influences. Many variants do not have any noticeable effect and simply represent natural genetic variation. Sometimes, though, a variant changes how a gene works more significantly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the ABCB11 gene can change the bile salt pump so it folds poorly, breaks down sooner, fails to reach the liver cell surface, or moves bile salts less effectively. This is how ABCB11 gene variants affect bile salt transport at the cellular level. Milder variants may leave some transport activity, while more severe variants can cause little to no activity, which often links to earlier or more persistent cholestasis.
How variants are linked to conditions
Pathogenic variants in the ABCB11 gene can cause progressive familial intrahepatic cholestasis type 2, and milder variants can lead to benign recurrent intrahepatic cholestasis type 2. Other ABCB11 gene variants are linked to a higher chance of intrahepatic cholestasis of pregnancy. For people reading about ABCB11 gene variants linked to liver conditions, common risk variants do not guarantee symptoms, while clearly pathogenic variants can confirm an inherited diagnosis.
A variant is not necessarily a diagnosis
Genetic variants are common across the general population and are a normal feature of human biology. Most do not directly affect health and simply reflect natural variation among people. For many genes, having a variant associated with a condition suggests a possible link rather than a confirmed diagnosis, particularly when several genes and environmental influences play a part. 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?
For many living with ABCB11 changes, risk is shaped most by the specific gene change itself. Pregnancy, birth control pills with estrogen, and some medicines can trigger or worsen bile flow problems in people who are susceptible. For severe inherited forms, lifestyle changes are not known to prevent the condition, but avoiding triggers may help limit flare-ups.
Inheritance of ABCB11 variants
For the most well-established ABCB11-related liver conditions, how ABCB11 gene variants are inherited follows an autosomal recessive pattern. This means a child inherits one ABCB11 variant from each parent, and parents are usually healthy carriers with one changed copy each. When both parents carry an ABCB11 variant, each pregnancy has a 25% chance of a child with the condition, a 50% chance of a carrier child, and a 25% chance of a child without the familial variants.
What does my ABCB11 result mean for my family?
For ABCB11, family meaning is usually discussed in the setting of a recessive liver condition. Brothers and sisters of an affected child may also be affected or may be healthy carriers, and parents are often carriers without symptoms. Other close relatives may also carry the variant, so the result can matter for family planning and for relatives who want to understand their own chance of being carriers.
Genetic information
Genetic testing
How you find out about variants
If bile flow problems run in your family or a liver test pattern suggests it, ABCB11 genetic testing looks for variants in the ABCB11 gene using a blood or saliva sample. A lab reads the gene’s DNA code and reports whether a variant linked to ABCB11-related cholestasis is found.
When should I consider getting a genetic test?
Consider ABCB11 genetic testing if you or your child has unexplained liver disease with poor bile flow, especially starting in infancy or childhood, or repeated episodes of itching and jaundice. It can also be helpful when there is a family history of ABCB11-related liver disease or unexplained early liver failure.
A genetic result is only one part of your health story
A genetic result can provide useful insight, but how much it explains varies by the condition and the type of variant. Over time, many factors affect how the body functions, including lifestyle, environment, age, and medical history. For some conditions, especially those shaped by many genes, genetic information provides context rather than certainty and is most helpful when considered alongside 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 personal experiences into perspective.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how your body handles some medicines. This helps explain why the same treatment may work well for one person, seem weaker in another, or cause more side effects in someone else. These differences are common and may influence how a drug is absorbed, moved through the body, broken down, or cleared, which can change both its benefits and your sensitivity to it.
What is Pharmacogenetics?
Pharmacogenetics examines the ways genetic differences affect how people respond to medicines. By studying links between genes and medications, it helps explain why the same treatment may work differently in different people. For many drugs, genes can influence how strongly a medicine works or how the body handles it. This information can support treatment decisions that are more informed and more individualized. More on this topic is available in the LearnHub.
Drugs influenced by the ABCB11 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medicine choice or dose, so questions about medication safety, side effects, or liver-related symptoms are best discussed with your doctor. ABCB11 has been studied in people who develop reduced bile flow or liver injury with some medicines, but this research is not used for routine prescribing.
History
Across cultures and time periods, inherited patterns of severe childhood cholestasis were noted long before the responsible gene was known. In the 1990s, studies of families with progressive familial intrahepatic cholestasis helped narrow the search to a region on chromosome 2. Soon after, researchers identified the ABCB11 gene as the cause of one major form, now called PFIC2. From these first observations, research expanded steadily, linking ABCB11 variants to milder recurring cholestasis and to some cases triggered by pregnancy or medicines. This discovery helped clarify why people with similar symptoms could have different inherited causes. Over time, descriptions became more precise as genetic testing connected earlier clinical reports with specific ABCB11 variants.