The ACVRL1 gene helps form and maintain healthy blood vessels by guiding signals between cells in vessel walls. If it does not work properly, blood vessels may develop in a fragile or unusual way. This can lead to frequent nosebleeds, small visible red spots on the skin, or abnormal links between arteries and veins in organs. Pathogenic variants in the ACVRL1 gene are a well known cause of hereditary hemorrhagic telangiectasia, an inherited condition that can affect people in different ways.
What is a gene?
Genes are segments of DNA that provide cells with instructions to make molecules or to regulate processes in the body. Some genes hold the information needed to produce proteins, the parts of cells that do much of the work. Other genes mainly control when certain processes take place, where they happen, and how strongly they operate. Taken together, genes affect how the body develops and functions, and they can influence how you respond to food, stress, or medications. To look into this topic more closely, you can learn more in LearnHub.
Overview
ACVRL1Gene function
What if the gene works
Your blood vessel lining cells use the ACVRL1 gene to respond to growth signals that guide blood vessel formation and repair. This helps vessels develop in a more organized, stable way.
Risk
What if the gene does not work
Pathogenic variants in the ACVRL1 gene most often cause hereditary hemorrhagic telangiectasia, leading to recurrent nosebleeds, visible blood vessel changes, and sometimes arteriovenous malformations in organs. Milder to more severe variants can influence when features appear and how extensive they are.
Treatment
What does that mean for your treatment
No ACVRL1-specific treatment or management approach is currently established in clinical guidelines; care is chosen by a person’s bleeding pattern and organ involvement rather than the ACVRL1 variant itself. The ACVRL1 gene, also called ALK1, is being studied as a drug target in abnormal blood vessel growth.
Conditions associated with ACVRL1
Gene function
What if the gene works
Healthy blood vessels need clear signals so they can grow, settle, and stay well formed. The ACVRL1 gene helps cells lining blood vessels respond to those signals, especially during growth and repair. This supports an organized network of arteries, veins, and tiny capillaries throughout the body.
The ACVRL1 gene helps endothelial cells, the cells that line blood vessels, receive growth and maintenance signals from the bloodstream. Its protein sits at the cell surface and passes those messages inward.
This gene helps blood vessel cells know when to grow, move, or slow down. That balanced signaling helps explain how the ACVRL1 gene affects blood vessel growth in a controlled, orderly way.
The ACVRL1 gene supports the careful shaping and remodeling of blood vessels as tissues grow and heal. It helps new vessel branches form in a more organized pattern instead of spreading at random.
Proper ACVRL1 activity helps blood vessels mature and remain steady over time. This supports strong connections between vessel lining cells and helps the vessel wall stay well structured.
What is a variant?
A genetic variant is a minor change 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 the way the body responds to environmental influences. Many have no noticeable effect and simply represent natural genetic variation. In some cases, though, a variant can affect how a gene works more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the ACVRL1 gene often weaken or silence a signaling protein on the cell surface of cells that line blood vessels. In hereditary hemorrhagic telangiectasia, how ACVRL1 gene variants affect blood vessel signaling can shape how early changes appear and how marked they become. Milder variants may leave some signaling intact, while more severe variants can prevent the protein from folding properly, reaching the cell surface, or signaling at all.
How variants are linked to conditions
Pathogenic variants in the ACVRL1 gene cause hereditary hemorrhagic telangiectasia type 2, so ACVRL1 gene variants linked to hereditary hemorrhagic telangiectasia are a well-established finding in medical genetics. People with this condition may have repeated nosebleeds, small visible widened blood vessels, and abnormal blood vessel connections in organs such as the lungs, liver, or brain. Some carrying an ACVRL1 gene variant may also develop pulmonary arterial hypertension, a form of high blood pressure in the lungs.
A variant is not necessarily a diagnosis
Genetic variants are a usual part of human biology and are common throughout the general population. Most do not have a direct effect on health and simply reflect natural human variation. For many genes, carrying a variant associated with a condition suggests a possible link rather than a definite diagnosis, especially when more than one gene and environmental factors are involved. In some situations, though, a single well-characterized variant in a particular gene is enough to confirm the diagnosis.
Are there things that can increase or change my risk?
For ACVRL1, the main risk comes from inheriting a disease-causing gene change, so lifestyle habits do not meaningfully change whether this condition develops. Signs often become more noticeable with age, and pregnancy can raise the chance of bleeding or other blood vessel problems in some people living with ACVRL1.
Inheritance of ACVRL1 variants
ACVRL1-related hereditary hemorrhagic telangiectasia is inherited in an autosomal dominant pattern. This means a person with a disease-causing variant in the ACVRL1 gene has a 50% chance of passing it on to each child, whether the child is a son or a daughter. In practical terms, how ACVRL1 variants are inherited usually means the variant is passed down through a family across generations. Some people have a new (de novo) variant, which started in them and was not inherited from either parent.
What does my ACVRL1 result mean for my family?
For many living with a disease-causing change in the ACVRL1 gene, close relatives can also carry the same change and may have nosebleeds, small widened blood vessels, or hidden blood vessel problems in organs even if symptoms seem mild. Parents, brothers, sisters, and children are the family members most likely to share it. Because ACVRL1-related hereditary hemorrhagic telangiectasia usually runs in families in a dominant way, each child of an affected parent has a 50% chance of inheriting the same gene change.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the ACVRL1 gene, doctors use a blood or saliva test. Genetic testing for variants in the ACVRL1 gene reads the DNA code and checks for changes linked to hereditary hemorrhagic telangiectasia. Results may show a disease causing variant, a harmless variant, or a change whose meaning is still unclear.
When should I consider getting a genetic test?
Consider ACVRL1 testing if you have frequent nosebleeds, small red spots on the lips, tongue, or fingers, abnormal blood vessels in organs, or a family history of hereditary hemorrhagic telangiectasia, an inherited blood vessel condition. Testing can also help relatives understand whether they carry the same gene change.
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 involved. Over time, factors such as lifestyle, environment, age, and medical history also shape how the body functions. For some conditions, especially those influenced by many genes, genetic information offers context rather than certainty and is most helpful when viewed alongside other parts of care. In other situations, a genetic result may give a clear answer. In areas like medication response, it can also help place personal experiences in context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how your body responds to medicines. This helps explain why the same treatment may work well for one person, seem less effective for another, or cause more side effects in someone else. Differences in how the body absorbs, breaks down, moves, or responds to a drug are common, and they can influence both benefit and sensitivity.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in genes affect the way people respond to medicines. It studies gene drug patterns to help explain why the same treatment can work differently from one person to another. With many medications, genes can influence how powerfully a drug works or how the body handles it. This information can support more informed, more individualized treatment choices. More detail on this topic is available in the LearnHub.
Drugs influenced by the ACVRL1 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in predicting medication response, so if you have questions about medicines, side effects, or treatment changes, it is best to talk with your doctor.
History
Hereditary hemorrhagic telangiectasia was first described in the late 1800s and early 1900s by Henri Rendu, William Osler, and Frederick Parkes Weber, long before its genetic causes were known. Families with frequent nosebleeds and small visible blood vessel changes helped doctors recognize that the condition could run from parent to child. In the 1990s, researchers began separating different genetic forms of the condition, first linking one form to the ENG gene and then identifying the ACVRL1 gene as a cause of another form. Building on this early work, scientists uncovered more about the ACVRL1 gene in 1996, when it was mapped to hereditary hemorrhagic telangiectasia type 2. That discovery helped clarify why people with similar symptoms could have different underlying gene variants.