The ASXL1 gene helps control when other genes are switched on or off, especially during early development and blood cell formation. When it does not work properly, growth, brain development, and the way the body builds tissues can be affected. This gene plays an important role in guiding normal development, so inherited pathogenic variants in the ASXL1 gene are linked to Bohring-Opitz syndrome, a rare condition that affects development and muscle tone. Acquired variants in blood cells may also play a role in some bone marrow conditions and blood cancers.
What is a gene?
Genes are sections of DNA that carry instructions your cells use to make molecules or regulate activities in the body. Some genes provide the code for proteins, which are the parts of cells that do much of the work. Others mainly direct when certain processes happen, where they take place, and how active they are. Together, genes influence how the body develops and works, and they can affect how you respond to food, stress, or medications. For a deeper look at this topic, you can learn more in the LearnHub.
Overview
ASXL1Gene function
What if the gene works
Your cells use the ASXL1 gene to help switch other genes on or off at the right time. This supports normal growth, development, and the making of blood cells.
Risk
What if the gene does not work
More disruptive variants in the ASXL1 gene can cause Bohring-Opitz syndrome, with developmental delay, feeding problems, poor growth, and distinctive physical features, while milder variants may have different effects. Acquired ASXL1 variants are also common in some blood cancers.
Treatment
What does that mean for your treatment
No ASXL1 specific treatment or management approach is currently established for a pathogenic or loss of function variant in the ASXL1 gene. In myeloid blood cancers, ASXL1 variants are used mainly as a prognostic biomarker and are being studied to refine risk groups and treatment response, rather than to choose a specific ASXL1 targeted drug.
Conditions associated with ASXL1
Gene function
What if the gene works
Your cells need careful control over which instructions are used at any moment. The ASXL1 gene helps manage that control by shaping how tightly DNA is packed and which genes stay active or quiet. Understanding what the ASXL1 gene does helps explain how cells keep their identity as they grow, divide, and mature.
The ASXL1 gene helps cells switch groups of genes on or off at the right time. It does this by working with other proteins that place or remove small chemical marks on DNA packaging proteins.
Inside the nucleus, the ASXL1 gene supports how DNA is wrapped and organized. This careful packaging helps cells reach the right instructions without opening all of their DNA at once.
By guiding gene activity, the ASXL1 gene helps cells keep their assigned roles. This matters as early cells become more specialized and need stable patterns of activity.
The ASXL1 gene supports the balance between self renewal and maturation in early cells. That balance helps tissues replace older cells in an orderly, controlled way over time.
What is a variant?
A genetic variant is a minor change in the DNA sequence of a gene. These changes are common and are part of normal human diversity, including differences in appearance, metabolism, and how the body responds to environmental influences. Many variants do not have any noticeable effect and simply represent natural genetic variation. In some situations, though, a variant can change the function of a gene more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the ASXL1 gene often make a shortened protein or reduce how much usable protein the cell has, disrupting key protein partners and changing how other genes are switched on or off. This is how ASXL1 gene variants change protein function in many cells. Some variants may only partly weaken this control, while more severe truncating variants often cause a larger disruption and can be linked to earlier or more marked features.
How variants are linked to conditions
Among the ASXL1 gene variants linked to health conditions, inherited pathogenic variants cause Bohring-Opitz syndrome, a rare condition associated with feeding difficulties, growth differences, and developmental delay. Acquired variants in the ASXL1 gene are also linked to some blood conditions, especially myelodysplastic syndromes and acute myeloid leukemia. These blood-related variants usually arise during life in blood cells rather than being passed down through a family.
A variant is not necessarily a diagnosis
Genetic variants are a routine part of human biology and are widely found in the general population. Most do not have a direct effect on health and simply reflect natural human diversity. For many genes, carrying a variant associated with a condition indicates a possible link rather than a definite diagnosis, especially when several genes and environmental factors also contribute. In some cases, though, a single well characterized variant in a specific gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For inherited ASXL1-related conditions, risk is mainly set by whether a disease-causing change in the ASXL1 gene is present, and these changes often happen for the first time in the child rather than being passed down. Family history can matter if a parent carries the change, including in only some egg or sperm cells. There is not enough evidence to say that lifestyle or environmental changes lower this genetic risk.
Inheritance of ASXL1 variants
ASXL1-related conditions such as Bohring-Opitz syndrome usually follow an autosomal dominant pattern, which means one altered copy of the ASXL1 gene can be enough to cause the condition. If a parent carries a disease-causing variant in the ASXL1 gene, each child has a 50% chance of inheriting it. In practice, how ASXL1 variants are inherited often includes a new, de novo variant, meaning the change starts in the child and was not inherited from either parent.
What does my ASXL1 result mean for my family?
For an inherited ASXL1 change linked to Bohring-Opitz syndrome, close relatives may also carry the same change, so parents, siblings, and future children can have family implications. This condition follows a dominant pattern, but many cases happen as a new change in the child, so a parent is not always the source. Family meaning can differ if an ASXL1 result was found only in blood cells later in life, because those changes are often not passed down.
Genetic information
Genetic testing
How you find out about variants
To look for an ASXL1 variant, ASXL1 genetic testing reads the DNA in a blood, saliva, or cheek swab sample. A lab checks the gene’s code for variants and reports whether one was found. Because ASXL1 changes can also arise over time in blood cells, results are interpreted carefully to tell inherited and acquired variants apart.
When should I consider getting a genetic test?
Testing for the ASXL1 gene may be considered if a baby or child has signs of Bohring-Opitz syndrome, a rare condition linked to developmental delay, feeding problems, poor growth, and a typical posture or facial appearance. An ASXL1 result found during blood or cancer testing may need follow-up to see whether the change is inherited or only in blood cells.
A genetic result is only one part of your health story
A genetic finding can provide useful insight, but how much it reveals depends on the condition and the type of variant identified. Many factors, including lifestyle, environment, age, and medical history, shape how the body works over time. For some conditions, especially those influenced by many genes, genetic information offers context rather than certainty and is most helpful when considered alongside other parts of care. In other situations, a genetic result can give a clear answer. In areas such as medication response, genetic results can also help place a person’s individual experiences in context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Some people break down a drug more slowly or more quickly than others, so the same treatment can lead to different effects or different chances of side effects. This kind of variation is common and can influence how well a medicine works or how sensitive a person is to it.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can affect the way a person responds to medications. By looking at connections between genes and drugs, it helps explain why the same treatment may work differently from one person to another. For many medicines, genes influence both how strongly a drug works and how the body processes it. This information can support more informed, individualized treatment decisions. More on this topic is available in the LearnHub.
Drugs influenced by the ASXL1 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding routine medication choices, so general questions about medicines, side effects, or treatment plans are best discussed with your doctor. ASXL1 changes are being studied in blood cancers because they may affect how some treatments work, but this is not yet a standard guide for most medicines.
History
ASXL1 first drew scientific interest when researchers recognized it as the human counterpart of a gene in fruit flies called additional sex combs, a finding that linked it to early work on growth and development. From these first observations, research expanded steadily. In the years that followed, changes in the ASXL1 gene were identified in people with Bohring Opitz syndrome, which helped connect the gene to a distinct inherited condition. Later, studies of blood cancers showed that acquired ASXL1 variants are common in several myeloid cancers, including myelodysplastic syndromes and acute myeloid leukemia. This work also helped establish ASXL1 as one of the genes often discussed in clonal hematopoiesis, when a blood cell population expands because of a genetic change.