The CHSY1 gene helps make chondroitin sulfate, a material that supports cartilage and guides early body development. This gene plays an important role in how bones and joints form, especially in the hands, feet, and face. If both copies do not work properly, a person can be born with a rare condition affecting bone growth and body patterning, often with short fingers or toes, joined digits, and sometimes hearing or vision differences.
What is a gene?
Genes are stretches of DNA that carry instructions cells use to make molecules or regulate activities in the body. Some provide the directions for building proteins, which are the parts of cells that do the work. Others mainly guide when certain processes happen, where they happen, and how active they are. Taken together, genes affect how the body develops and functions, and they can also shape your response to food, stress, and medications. More detailed information on this topic is available in the LearnHub.
Overview
CHSY1Gene function
What if the gene works
The CHSY1 gene helps make chondroitin sulfate, a sugar chain used in cartilage and other connective tissues. It supports normal shaping and growth of bones, joints, and parts of the face and limbs.
Risk
What if the gene does not work
Variants in the CHSY1 gene can disturb bone growth, most often causing Temtamy preaxial brachydactyly syndrome with hand and foot differences and characteristic facial features. Milder or more severe variants may affect which features appear and how marked they are.
Treatment
What does that mean for your treatment
No treatment or management approach tied to the CHSY1 gene is currently established for people with a pathogenic variant. Care is based on the person’s features and symptoms rather than on a drug choice linked to CHSY1. The CHSY1 gene is being studied in cartilage biology and in some cancers as a possible biomarker or treatment target, but this has not led to guideline based therapy.
Conditions associated with CHSY1
Gene function
What if the gene works
CHSY1 helps your body build and organize cartilage, the smooth, springy tissue that supports joints and shapes growing bones. It does this by helping cells make chondroitin sulfate, a long sugar chain that gives tissues structure and cushioning. This everyday job is especially important during growth and body shaping.
The CHSY1 gene helps cells make chondroitin sulfate, a long sugar chain used in cartilage and other supportive tissues. This is a key part of what the CHSY1 gene does in the body to help build cartilage during growth.
Chondroitin sulfate helps tissues hold water and stay springy. That gives cartilage its smooth, shock-absorbing quality and helps joints move in a more controlled way.
By supporting the material around cells, the CHSY1 gene helps guide how developing bones, joints, and facial tissues take shape. This steady framework also helps cells receive and respond to growth signals.
What is a variant?
A genetic variant is a minor difference in the DNA sequence within a gene. These differences are common and help shape normal human diversity, including differences in appearance, metabolism, and the way the body reacts to environmental influences. Many variants do not cause any noticeable effects and are simply part of natural genetic variation. In some situations, though, a variant can change how a gene works more significantly and may contribute to, or directly cause, a genetic condition.
Genetic variants
What if the gene does not work
CHSY1 gene variants can weaken or shut down the enzyme that builds chondroitin sulfate chains, so cells make shorter or fewer of these structural sugar chains. More disruptive variants, such as early stop or splice changes, often cause a larger loss of enzyme activity than some missense variants, which may leave partial function. This change can disrupt cell signaling during bone and tissue development, and greater loss of function is often linked to earlier or more noticeable features.
How variants are linked to conditions
Pathogenic variants in both copies of the CHSY1 gene cause Temtamy preaxial brachydactyly syndrome, a rare inherited condition that mainly affects the hands and feet. People with CHSY1 gene variants linked to this syndrome may also have differences in facial features, hearing, or teeth, although the pattern can vary from person to person.
A variant is not necessarily a diagnosis
Genetic variants are a routine feature of human biology and are widely seen across the general population. Most do not directly affect health and simply reflect natural variation among people. In many genes, having a variant associated with a condition points to a possible link rather than a confirmed diagnosis, particularly when several genes and environmental influences also play a role. In other situations, one well-defined variant in a particular gene is enough to establish the diagnosis.
Are there things that can increase or change my risk?
For CHSY1, risk is mainly changed by family genetics rather than lifestyle. A child’s chance of having a CHSY1-related condition is higher when both parents carry a harmful CHSY1 change, and this can be more likely in families where the parents are blood relatives. There is not enough evidence to say that diet, exercise, or other daily habits lower this risk.
Inheritance of CHSY1 variants
For families asking about the CHSY1 gene inheritance pattern, the best-established pattern is autosomal recessive. This means a person usually inherits one altered copy of the CHSY1 gene from each parent. Parents who each carry one variant are typically unaffected, but with each pregnancy there is a 25% chance of having an affected child, a 50% chance the child will be a carrier, and a 25% chance the child will inherit neither variant. Sons and daughters are affected at the same rate.
What does my CHSY1 result mean for my family?
Changes in the CHSY1 gene are linked to a rare inherited condition that usually runs in families in a recessive pattern. For family members, this often means parents may be healthy carriers, brothers and sisters could also be affected or be carriers, and relatives who are planning children may also want to know about their carrier status. The chance for other relatives depends on how closely related they are and whether the same gene change is present in the family.
Genetic information
Genetic testing
How you find out about variants
To find variants in the CHSY1 gene, doctors use genetic testing on a blood or saliva sample. A lab reads the DNA code and looks for changes linked to conditions associated with the CHSY1 gene. CHSY1 genetic testing can help confirm whether a variant is present and whether it may explain a person’s features or symptoms.
When should I consider getting a genetic test?
Consider CHSY1 testing if a child has unusual thumb or toe development, short fingers, or a pattern of bone and facial differences that doctors suspect may be inherited, especially if similar features run in the family. Testing can help confirm whether a change in the CHSY1 gene is the cause.
A genetic result is only one part of your health story
A genetic test result can be informative, but what it tells you varies depending on the condition and the kind of variant involved. Over time, factors such as lifestyle, environment, age, and medical history also affect how the body works. For some conditions, especially those influenced by many genes, genetic information offers context rather than certainty and is best understood 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 perspective.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can influence how people respond to medicines. Small differences in genes can change how the body breaks down, moves, or responds to a drug, so the same treatment may work differently from one person to another. These differences are common and may affect how much benefit a medicine gives or how sensitive someone is to side effects.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in a person’s genes affect their response to medications. It studies gene and drug patterns to help explain why the same treatment may work differently from one person to another. For many medicines, genes influence how strongly a drug works or how the body handles it. This information can support more informed and individualized treatment decisions. To explore this topic in more detail, you can learn more in the LearnHub.
Drugs influenced by the CHSY1 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. Questions about side effects, benefits, or how a medication fits your health history are best discussed with your doctor or pharmacist.