The TMEM240 gene gives your body instructions for a small protein found in cell membranes, especially in brain areas that help control balance, coordination, and speech. This gene plays an important role in keeping these nerve cells working smoothly. Pathogenic variants in the TMEM240 gene can cause spinocerebellar ataxia type 21, a condition that may lead to an unsteady walk, tremor, slurred speech, and sometimes learning or behavior differences. TMEM240 is mainly discussed in neurology and genetics rather than popular culture.
What is a gene?
Genes are stretches of DNA that carry instructions your cells use to make molecules or regulate activities in the body. Some genes provide the information needed to produce proteins, the parts of cells that do the work. Others mainly direct when certain processes take place, where they happen, and how active they are. Together, genes affect how the body develops and works, and they can also influence how you respond to food, stress, or medications. To go into this topic in more detail, you can read more in the LearnHub.
Overview
TMEM240Gene function
What if the gene works
The TMEM240 gene gives cells instructions for a small membrane protein, especially active in the brain. It appears to support normal nerve cell function and movement control.
Risk
What if the gene does not work
Variants in the TMEM240 gene are linked to spinocerebellar ataxia type 21, which can cause unsteady walking, poor coordination, tremor, and learning difficulties. Effects range from milder to more severe, which may influence onset and daily function.
Treatment
What does that mean for your treatment
At present, no treatment or management approach specifically tied to a pathogenic or loss-of-function variant in the TMEM240 gene is established in clinical guidelines. Research on the TMEM240 gene is still early, including work on its possible role as a biomarker in some cancers.
Conditions associated with TMEM240
Gene function
What if the gene works
The TMEM240 gene is most active in brain regions that help coordinate movement. It gives cells instructions for a small protein that is built into the cell membrane. This background helps explain what the TMEM240 gene does in the brain: it supports the everyday function of nerve cells involved in smooth, steady movement.
This gene gives cells instructions for a small protein that is built into the cell membrane. From this position, it takes part in the routine activity that helps nerve cells work day to day.
The TMEM240 gene is especially active in the cerebellum, the part of the brain that fine tunes balance and movement. When it works properly, it supports normal function in nerve cells involved in coordination.
What is a variant?
A genetic variant is a minor change in the DNA sequence within a gene. These changes are common and help shape normal human diversity, including differences in appearance, metabolism, or how 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 affect gene function more strongly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Many variants in the TMEM240 gene are missense changes that swap one protein building block for another. Studies of how TMEM240 gene variants affect nerve cells suggest these changes can alter the protein’s shape, reduce its stability, or keep it from reaching the right place in the cell membrane. Some variants may leave partial function, while more disruptive ones can interfere more strongly and, in SCA21, may be linked to earlier onset or a wider range of symptoms.
How variants are linked to conditions
Pathogenic variants in the TMEM240 gene cause spinocerebellar ataxia type 21, a rare inherited condition that mainly affects balance and coordination. When doctors discuss TMEM240 gene variants linked to spinocerebellar ataxia type 21, they are referring to this well-established diagnosis. Symptoms can begin in childhood or adulthood and may vary within the same family.
A variant is not necessarily a diagnosis
Gene variants are a normal feature of human biology and are common throughout the general population. Most variants do not have a direct effect on health and simply represent natural human diversity. For many genes, carrying a variant associated with a condition suggests a possible link rather than a definite diagnosis, especially when multiple genes and environmental factors also contribute. In some situations, though, a single well-characterized variant in a particular gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
There is not yet broadly confirmed evidence on specific factors that increase or reduce risk related to the TMEM240 gene. For many living with a TMEM240 change, the main factor is the genetic variant itself, and a doctor or genetic counselor can help explain what it may mean for personal and family risk.
Inheritance of TMEM240 variants
TMEM240-related ataxia is usually inherited in an autosomal dominant pattern. In practical terms, how TMEM240 gene variants are inherited means one altered copy can be enough to cause the condition, and a parent with the variant can pass it to a child with a 50% chance in each pregnancy. The variant can be inherited from either the mother or the father. Some people have a new, de novo variant in the TMEM240 gene that was not inherited from either parent.
What does my TMEM240 result mean for my family?
For TMEM240, the main known family pattern is dominant, which means close relatives such as a parent, brother, sister, or child may also carry the same gene change. In families with a TMEM240-related condition, relatives can sometimes have similar balance, coordination, or learning-related features, while others may be affected more mildly. Because of this, family members may also want to learn whether the variant is present in them.
Genetic information
Genetic testing
How you find out about variants
Testing for variants in the TMEM240 gene uses a blood or saliva sample. In TMEM240 genetic testing for inherited ataxia, a lab reads the gene's DNA code to look for changes and compares them with known variants. Results may show a variant linked to disease, a harmless variant, or a change whose meaning is still unclear.
When should I consider getting a genetic test?
You may want to consider TMEM240 testing if you or close relatives have an inherited pattern of balance problems, shaky movements, poor coordination, or speech changes, especially starting in childhood or early adult life. Changes in the TMEM240 gene are linked to a rare condition called spinocerebellar ataxia type 21.
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 kind of variant involved. How the body functions over time is also shaped by many influences, including lifestyle, environment, age, and medical history. In some conditions, especially those affected by many genes, genetic information offers context rather than certainty and is most helpful when viewed together with other parts of care. In other situations, a genetic result may give a clear answer. In areas like medication response, genetic results can also help put individual experiences into context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Small differences in DNA can change how the body breaks down a drug, moves it through the body, or responds to it at its target. This helps explain why the same treatment works well for one person, works less well for another, or causes more side effects in some people.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences affect the way people respond to medications. By looking at links between genes and drugs, it helps explain why the same treatment can work differently from one person to another. For many medicines, genes can influence how strongly a drug works or how the body handles it. This information can support more informed, individualized treatment decisions. More detailed information on this topic is available in the LearnHub.
Drugs influenced by the TMEM240 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding how medicines are chosen or used, so any concerns about your health, new symptoms, or possible medicine side effects are best discussed with your doctor.
History
TMEM240 entered the medical literature relatively recently through studies of families with an inherited form of coordination and balance problems, later classified as spinocerebellar ataxia type 21. In recent decades, awareness of this gene’s role has grown as sequencing methods made it easier to link shared symptoms across generations to a specific DNA change. Early reports centered on a small number of affected families, which helped establish TMEM240 as the cause of this rare condition in some people. From these first observations, research expanded steadily, and additional families from different countries were described. This history is mainly a story of modern gene discovery rather than a widely known public health milestone.