The HEXB gene provides instructions for a protein that helps form enzymes that clear certain fatty materials from cells, especially in the brain and nerves. This gene helps your body recycle these substances so nerve cells can keep working normally. If this process does not work well, fatty material builds up and can cause Sandhoff disease, a genetic condition that may lead to loss of skills, muscle weakness, seizures, and vision or hearing changes. Some people develop symptoms in infancy, while others have later-onset forms.
What is a gene?
Genes are stretches of DNA that hold instructions your cells use to make molecules or direct processes in the body. Some provide the code for proteins, which do much of the cell’s work. Others are involved mainly in regulating when certain processes happen, where they happen, and how active they are. Taken together, genes affect how the body grows and works, and they can influence how you respond to food, stress, and medicines. For a deeper look at this topic, you can read more in the LearnHub.
Overview
HEXBGene function
What if the gene works
The HEXB gene helps cells break down certain fatty materials inside lysosomes, the cell’s recycling centers. This supports healthy nerve cell function and normal brain development.
Risk
What if the gene does not work
Pathogenic variants in the HEXB gene can cause Sandhoff disease, which affects the brain and nerves. More severe variants often appear in infancy with developmental loss and seizures, while milder variants may cause later-onset weakness, balance problems, or psychiatric symptoms.
Treatment
What does that mean for your treatment
For pathogenic variants in the HEXB gene, no HEXB specific treatment or drug choice is currently established in clinical guidelines. Care is based on symptom relief and supportive therapies rather than a gene directed medicine. HEXB related GM2 gangliosidosis is under study in gene therapy and other disease modifying approaches, but these are not yet standard care.
Conditions associated with HEXB
Gene function
What if the gene works
Inside your cells, the HEXB gene supports the lysosome, a recycling center that breaks down old materials. Its protein becomes part of cleanup enzymes that process certain fats and substances with sugars attached. This steady work helps cells stay balanced and keeps normal cell turnover moving smoothly.
Its protein joins with a partner from the HEXA gene, or with another copy of itself, to make working cleanup enzymes. These enzymes let lysosomes handle different materials in an orderly way.
One enzyme containing the HEXB protein helps break down GM2 ganglioside, a fatty material found in cell membranes. This is part of how the HEXB gene helps cells recycle fats and sugars during normal daily upkeep.
Enzymes that contain the HEXB protein remove certain sugar groups from larger molecules so those molecules can be taken apart step by step. This supports routine recycling of membrane pieces and other cell materials.
What is a variant?
A genetic variant is a small change in the DNA sequence within a gene. These changes are common and are part of 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 reflect natural genetic variation. In some situations, however, a variant can change a gene’s function more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
When looking at how variants influence the HEXB gene's function, some changes make the HEXB protein fold poorly, break down early, or fail to join the enzyme complex properly, so cells clear certain fatty materials less effectively. More severe variants can leave little or no enzyme activity, while milder variants may preserve some activity. This range often shapes whether Sandhoff disease begins earlier and is more intense or appears later with a less severe course.
How variants are linked to conditions
Pathogenic variants in the HEXB gene cause Sandhoff disease, a rare inherited condition that mainly affects the brain and nerves. This is the main well-established HEXB gene condition described in human genetics. Symptoms may begin in infancy, childhood, or adulthood, so people can have very different patterns of movement, balance, strength, and learning or thinking changes. A confirmed disease-causing variant in the HEXB gene can establish the diagnosis.
A variant is not necessarily a diagnosis
Gene variants are a normal feature of human biology and are common across 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 are involved. In some instances, though, a single well-characterized variant in a particular gene can be enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For HEXB, the main risk factor is inherited: a child is at risk for Sandhoff disease only if both biological parents carry a harmful HEXB change. In families with known changes, family history and parents being related by blood can raise the chance, while day-to-day lifestyle does not meaningfully change this inherited risk.
Inheritance of HEXB variants
HEXB-related conditions such as Sandhoff disease are inherited in an autosomal recessive pattern. This means a child usually inherits one HEXB gene variant from each parent. Parents who each carry one variant are often unaffected themselves, but with each pregnancy they have a 25% chance of having an affected child, a 50% chance of having a child who is a carrier, and a 25% chance of having a child who inherits neither variant. This is the main pattern described when explaining how HEXB gene variants are inherited.
What does my HEXB result mean for my family?
For families with a HEXB-related condition, close relatives may also carry the same gene change even if they feel completely well. Brothers and sisters of an affected child may also be affected or be carriers, and parents are usually carriers. Other relatives, such as aunts, uncles, and cousins, may also carry the change, so the result can matter beyond one person.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for HEXB variants uses a blood or saliva sample to read the HEXB gene and look for changes linked with disease or carrier status. Results can help confirm a diagnosis, clarify whether you carry a familial variant, or show that no disease causing variant was found in the areas tested.
When should I consider getting a genetic test?
Consider genetic testing for the HEXB gene if a baby or child has signs of Sandhoff disease, such as losing skills they had gained, muscle weakness, seizures, or worsening vision or hearing, or if this condition runs in the family. Testing can also help clarify whether someone is a carrier when a relative has a known HEXB gene change.
A genetic result is only one part of your health story
A genetic result can provide useful insight, but what it can tell you varies depending on the condition and the kind of variant involved. The way the body functions over time is also shaped by many factors, including lifestyle, environment, age, and medical history. For some conditions, especially those influenced by many genes, genetic information provides context rather than certainty and is best considered together with other parts of care. In other situations, a genetic result may offer a clear answer. In areas such as medication response, genetic results can also help put individual experiences into perspective.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Small differences in genes that help the body absorb, break down, transport, or respond to a drug can mean the same treatment works well for one person, works less well for another, or causes more side effects. This kind of variation is common and helps explain why medication response can differ even when people take the same dose. Genetics is only one part of the picture, alongside age, liver and kidney function, other medicines, and overall health.
What is Pharmacogenetics?
Pharmacogenetics is the area of study that looks at how genetic differences affect the way medications work in each person. It examines links between genes and drugs to help explain why the same treatment may have different effects from one person to another. For many medicines, genes can influence how strongly a drug works or how the body processes it. This information can support treatment decisions that are more informed and more individualized. To explore this subject in greater depth, you can learn more in the LearnHub.
Drugs influenced by the HEXB 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 any questions about medications, side effects, or treatment changes are best discussed with your doctor.
History
In 1968, physician Konrad Sandhoff described a rare inherited condition that was distinct from Tay-Sachs disease, marking an important step in the history of the HEXB gene. Initially understood through missing enzyme activity rather than DNA itself, the condition helped researchers separate closely related lysosomal diseases. Building on this early work, scientists linked the problem to the HEXB gene and later mapped it to chromosome 5. As genetic methods improved in the late 20th century, the HEXB gene was sequenced and different disease-causing variants were identified in affected families. These advances helped clarify diagnosis, carrier testing, and the broader history of inherited nerve cell storage conditions.