The TBXT gene helps guide early development of the spine and nearby tissues while a baby is growing in the womb. This gene plays an important role in forming the notochord (an early structure that helps organize the backbone). If it does not work as expected, some people may be born with changes in the bones of the spine or tailbone. Certain TBXT variants are also linked to a higher chance of chordoma, a rare tumor that can grow from leftover notochord cells.
What is a gene?
Genes are stretches of DNA that carry instructions your cells use to make molecules or regulate activities in the body. In some cases, those instructions are used to produce proteins, which do much of the cell’s work. Other genes mainly direct when certain processes happen, where they take place, and how active they are. Taken together, genes affect how the body grows and works, and they can also shape how you respond to food, stress, or medicines. For a deeper look at this topic, you can learn more in the LearnHub.
Overview
TBXTGene function
What if the gene works
The TBXT gene helps guide very early embryo development. It switches other genes on and off to shape the body axis and support tissues that guide spine development.
Risk
What if the gene does not work
Changes in the TBXT gene can lead to vertebral differences present from birth and may increase susceptibility to chordoma, a rare bone cancer. Milder and more severe variants can differ in which spinal features appear and how pronounced they are.
Treatment
What does that mean for your treatment
No treatment or drug choice tied specifically to a pathogenic variant in the TBXT gene is currently established. In chordoma, the TBXT gene is being studied as a biomarker and possible treatment target, but this has not yet changed routine care.
Conditions associated with TBXT
Gene function
What if the gene works
Early in pregnancy, your body uses the TBXT gene to organize the growing embryo. It gives developing cells timing and position cues that help shape the body's main axis and the tissues along the future spine. Understanding what the TBXT gene does in early development helps explain how the body plan is set up from the start.
Early in development, the TBXT gene helps set up the embryo's head-to-tail body plan. This gives cells position cues so growing tissues line up in the right order.
Inside early cells, the TBXT gene makes a transcription factor (a protein that switches other genes on or off). This helps coordinate gene activity needed for organized growth.
Activity from the TBXT gene guides some early cells toward mesoderm, the middle cell layer that later helps form muscle, bone, and connective tissue. This step supports the body's basic tissue plan.
During early growth, the TBXT gene supports formation of the notochord, a temporary rod-like structure that helps guide the future spine and nearby tissues. Its signals help surrounding cells develop in an orderly pattern.
What is a variant?
A genetic variant is a minor change in the DNA sequence of a gene. These changes are common and form part of normal human diversity, such as differences in appearance, metabolism, or 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 TBXT gene reduce how well the brachyury protein binds DNA or controls other genes, while more disruptive variants can sharply lower the amount of working protein or stop it being made. This helps show how variants influence the TBXT gene's function across a spectrum, from milder changes with partial activity to severe loss of function. In people with TBXT-related vertebral conditions, lower remaining activity can be linked to earlier or more extensive changes in spine formation.
How variants are linked to conditions
Variants involving the TBXT gene are most clearly linked to chordoma, a rare tumor that can develop at the base of the skull or along the spine. Inherited extra copies of the TBXT gene and some rare variants are associated with familial chordoma, while other common variants near this gene are linked to a higher chance of sporadic chordoma in population studies. For the common risk-associated variants, this reflects increased risk rather than a certain diagnosis.
A variant is not necessarily a diagnosis
Gene variants are a normal feature of human biology and are common throughout the general population. Most have no direct impact on health and simply reflect natural human diversity. For many genes, carrying a variant associated with a condition suggests a possible link rather than a definite diagnosis, especially when several genes and environmental factors contribute. In some situations, 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 TBXT, the clearest risk change comes from inheriting certain rare changes, especially extra copies of the gene, which are linked to a much higher chance of chordoma, a rare bone tumor. There is not enough evidence to say that lifestyle or environmental factors specifically lower or raise TBXT-related risk.
Inheritance of TBXT variants
The inheritance of TBXT gene variants depends on the specific condition and the type of gene change involved. Some TBXT gene changes linked to familial chordoma are inherited in an autosomal dominant pattern, which means a parent carrying the variant can pass it to each child with a 50% chance. This is the main well-established answer to how TBXT gene variants are inherited in families, although not everyone who inherits a TBXT-related variant will necessarily develop the same health problem.
What does my TBXT result mean for my family?
Some TBXT changes linked to inherited chordoma risk can run in families in a dominant way, so close relatives such as parents, brothers, sisters, and children may also carry the same change. For many families, this means first-degree relatives may want to learn whether the result applies to them as well. The exact family impact depends on the specific TBXT result and the condition it is tied to.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for TBXT variants usually uses a blood or saliva sample. A lab reads the DNA in the TBXT gene, either checking for a known variant or looking across many genes at once, to show whether a TBXT variant is present.
When should I consider getting a genetic test?
Genetic testing for the TBXT gene may be worth discussing if you or several close relatives have had chordoma, a rare cancer that starts in the bones of the skull base or spine. In that setting, testing can help clarify whether an inherited TBXT change may be part of the reason.
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 on the kind of variant involved. Over time, the way the body functions is also shaped by many factors, including lifestyle, environment, age, and medical history. For some conditions, particularly those affected by many genes, genetic information offers context rather than certainty and is most useful when considered with other parts of care. In other situations, a genetic result can give a clear answer. In areas like medication response, genetic results can also help put personal experiences into context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. This helps explain why the same treatment works well for one person, has little effect in another, or causes more side effects in someone else. Small differences in how the body absorbs, breaks down, or responds to a drug are common and can shape both benefit and sensitivity. Medication response is also influenced by age, liver and kidney function, other medicines, and overall health.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in genes can affect the way a person responds to medications. It studies gene drug patterns to help explain why the same treatment may work differently in different people. For many medicines, genes can influence both how strongly a drug works and how the body handles it. This information can support treatment choices that are more informed and more individualized. More detail on this topic is available in the LearnHub.
Drugs influenced by the TBXT gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in predicting how medicines will work, so questions about side effects, drug choice, or treatment changes are best discussed with your doctor. TBXT has been studied in cancer research, especially chordoma, as a possible treatment target, but it is not used in routine prescribing decisions.
History
The story of the TBXT gene began in early mouse studies, when researchers noticed animals born with unusually short tails and named the trait brachyury, meaning “short tail.” First described in the scientific literature as part of early genetics, this trait later became linked to a specific gene that helped shape ideas about how body form develops before birth. From these first observations, research expanded steadily. In the 1990s, scientists identified the human version, now called the TBXT gene, and connected it to rare tumors such as chordoma, which raised its profile in both developmental biology and cancer research. Over time, scientists’ understanding of the gene’s role has changed, moving from visible traits in animals to a clearer picture in human health.