The GAN gene helps nerve cells keep their internal support structure and protein cleanup system working properly. This gene plays an important role in keeping long nerve fibers healthy so signals can travel smoothly between the brain, spinal cord, and muscles. When both copies of the gene have pathogenic variants, nerve cells can be damaged, causing giant axonal neuropathy, a rare inherited condition. People with this condition may develop weakness, trouble walking, poor balance, and often tightly curly hair, usually starting in childhood.
What is a gene?
A gene is a stretch of DNA that carries instructions your cells use to make molecules or regulate processes in the body. Some genes hold the information needed to produce proteins, the working parts of cells. Other genes mainly help direct when certain processes happen, where they happen, and how strongly they run. As a whole, genes influence how the body develops and functions, and they can affect how you respond to food, stress, or medications. For a deeper look at this topic, you can find more in the LearnHub.
Overview
GANGene function
What if the gene works
The GAN gene helps cells clear and organize scaffold proteins, especially in nerve cells. This supports healthy axons, the long nerve fibers that carry signals through the body.
Risk
What if the gene does not work
Variants in the GAN gene can cause giant axonal neuropathy, which affects nerves and often leads to balance problems, weakness, and trouble walking. Milder or more severe variants may change when symptoms begin and how many body systems are affected.
Treatment
What does that mean for your treatment
No GAN-specific treatment or drug choice is currently established for people with a pathogenic or loss-of-function variant in the GAN gene. Gene therapy aimed at the GAN gene is under study, but it remains investigational.
Conditions associated with GAN
Gene function
What if the gene works
In nerve cells, smooth signaling depends on a tidy internal support system. The GAN gene helps manage that system by keeping key structural proteins in balance. This is part of what the GAN gene does in nerve cells and other tissues. It supports cell shape, transport, and routine upkeep.
The GAN gene helps control the cell’s internal framework, which gives cells shape and support. It keeps structural fibers in a more organized arrangement, especially in long nerve cells.
Its protein helps tag certain structural proteins so the cell can break them down when they are no longer needed. This cleanup helps keep the inner environment balanced and less cluttered.
In nerve cells, an organized inner framework helps materials move from one part of the cell to another. By keeping that framework steady, the GAN gene supports routine movement of supplies along the cell.
Balanced structural proteins help cells handle everyday movement, stretching, and maintenance. The GAN gene supports this steady state so cells can keep their shape while doing normal work.
What is a variant?
A genetic variant is a small alteration in the DNA sequence within a gene. These changes are common and help account for normal human differences, such as appearance, metabolism, or the way the body responds to environmental influences. Many variants do not lead to any noticeable effect and simply represent natural genetic variation. In some cases, though, a variant can affect 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 GAN gene variants make gigaxonin too short, unstable, or misshapen, which helps explain how GAN gene variants affect nerve cells. As a result, certain structural proteins build up inside cells and disrupt the cell's internal framework and transport system, a key part of giant axonal neuropathy. Milder variants may leave some protein activity, while more severe variants can nearly abolish it, often influencing how early symptoms begin and how strongly movement and sensation are affected.
How variants are linked to conditions
Pathogenic variants in the GAN gene cause giant axonal neuropathy, a rare inherited condition linked to progressive nerve problems that can affect walking, strength, sensation, and balance. In someone with signs of this condition, finding pathogenic variants in both copies of the GAN gene can confirm the diagnosis of giant axonal neuropathy. This is the main well-established condition associated with the GAN gene.
A variant is not necessarily a diagnosis
Genetic variants are a usual part of human biology and are widely present in the general population. Most do not have a direct effect on health and simply reflect normal human diversity. For many genes, carrying a variant associated with a condition indicates a possible link rather than a definite diagnosis, especially when multiple genes and environmental factors play a role. In some situations, however, 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 GAN, risk is mainly shaped by genetics rather than lifestyle. A child is at risk of this nerve condition when they inherit a changed GAN copy from both parents, so family history and whether both parents are carriers are the main factors that change risk.
Inheritance of GAN variants
GAN gene variants linked to giant axonal neuropathy are inherited in an autosomal recessive pattern. This means a child usually inherits one changed copy of the GAN gene from each parent. Parents who carry one variant are typically unaffected carriers, but with each pregnancy they have a 25% chance of having an affected child, a 50% chance of having a child who is also a carrier, and a 25% chance of having a child with two typical copies. This GAN gene inheritance pattern affects males and females equally.
What does my GAN result mean for my family?
For families, a GAN result usually means the condition follows a recessive pattern, so parents are often healthy carriers. Brothers and sisters may also have the condition or be carriers, and other close relatives may carry the same gene change without knowing it. This can matter for family planning and for relatives who want to understand their own chance of being carriers.
Genetic information
Genetic testing
How you find out about variants
To find out about variants in the GAN gene, a lab usually tests DNA from a blood sample or cheek swab. This genetic testing reads the gene’s code and compares it with the usual sequence to identify changes, which may be reported as benign, uncertain, or disease causing.
When should I consider getting a genetic test?
Testing for changes in the GAN gene may be worth considering if a child has early problems with walking, balance, and weakness that keep getting worse, especially along with very tightly curled hair. It can also help when there is a family history of giant axonal neuropathy, a rare nerve condition, or when a sibling has already been diagnosed.
A genetic result is only one part of your health story
A genetic finding can be very informative, but what it can tell you varies with the condition and the kind of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, influence how the body functions. For some conditions, especially those shaped by many genes, genetic information offers context rather than certainty and is most useful alongside other parts of care. In other situations, a genetic result may give a clear answer. In medication response, it can help make sense of individual experiences.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can influence how your body handles certain medicines. This helps explain why the same treatment may work well for one person, cause more side effects in another, or seem to have less effect than expected. These differences are common and often relate to how the body breaks down, moves, or responds to a drug.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can shape a person’s response to medicines. By studying links between genes and medications, it helps explain why the same treatment may work differently from one person to another. For many drugs, genes can affect both how strongly a medicine works and how the body processes it. This information can support treatment decisions that are more informed and more individualized. More detail on this topic is available in the LearnHub.
Drugs influenced by the GAN gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in predicting how someone will respond to medicines, so general medication questions are best discussed with your doctor or pharmacist. Seek medical advice if you notice new side effects, feel worse after starting a treatment, or have concerns about how medicines fit with your overall health.
History
Throughout history, people have described features that hinted at this gene. Giant axonal neuropathy was first described in the 1970s as a rare inherited nerve condition seen in children with progressive weakness and often tightly curled hair. In the late 1990s, researchers mapped the condition to chromosome 16 and identified changes in the GAN gene as the cause. This discovery gave families a clearer explanation for a condition that had previously been recognized mainly by its clinical features and nerve biopsy findings. From these first observations, research expanded steadily, including work on how to confirm the diagnosis with genetic testing. More recently, the GAN gene has also drawn attention through efforts to develop gene therapy for people living with giant axonal neuropathy.