The SLC17A5 gene gives cells instructions for a protein that moves sialic acid, a sugar your body uses on cell surfaces, out of the cell’s recycling spaces. This gene plays an important role in keeping that sugar from building up where it should not. When the SLC17A5 gene does not work properly, sialic acid can collect inside cells, especially in the brain and nervous system. Pathogenic variants in the SLC17A5 gene can cause free sialic acid storage disease, including Salla disease, with symptoms such as low muscle tone, movement and balance problems, developmental delay, and learning difficulties.
What is a gene?
Genes are stretches of DNA that give your cells instructions for making molecules or regulating activities in the body. Some genes carry the code for proteins, the parts of cells that do much of the work. Others mainly guide when certain processes happen, where they happen, and how strongly they run. Together, genes affect how the body develops and works, and they can help shape how you respond to food, stress, or medications. To explore this topic in more detail, you can visit the LearnHub.
Overview
SLC17A5Gene function
What if the gene works
The SLC17A5 gene helps cells move sialic acid, a natural sugar, out of recycling compartments called lysosomes. This supports normal recycling of cell materials, especially in the brain and nervous system.
Risk
What if the gene does not work
Variants in the SLC17A5 gene cause sialic acid storage disease, ranging from milder Salla disease to a more severe infantile form that often starts earlier. People may have developmental delay, low muscle tone, movement and balance problems, and sometimes seizures.
Treatment
What does that mean for your treatment
A pathogenic or loss-of-function variant in the SLC17A5 gene does not currently point to a proven gene-specific treatment or a drug choice used in guidelines. Care is symptom-based, with therapies chosen for the person’s needs rather than the variant itself. Early-stage research is exploring gene-based treatments for conditions linked to the SLC17A5 gene.
Conditions associated with SLC17A5
Gene function
What if the gene works
Inside your cells, the SLC17A5 gene supports the lysosome, a small compartment that breaks down and recycles used materials. Its protein mainly moves free sialic acid, a sugar released during this cleanup, back into the rest of the cell. This steady transport explains the core SLC17A5 gene function in everyday cell recycling.
The SLC17A5 gene makes a transporter protein that sits in the lysosome membrane. It carries free sialic acid from inside the lysosome to the cell fluid outside it.
This movement happens after cells break down old sugar coated proteins and fats in lysosomes. By returning the released sugar to the cell, it supports normal reuse and processing of these materials.
What is a variant?
A genetic variant is a minor change in the DNA sequence within a gene. These changes are common and are part of normal human diversity, including differences in appearance, metabolism, and how the body responds to environmental influences. Many variants have no noticeable effect and simply represent natural genetic variation. In some situations, 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
Variants in the SLC17A5 gene can change the sialin protein so it folds poorly, breaks down sooner, reaches the lysosome (the cell’s recycling compartment) less reliably, or moves sialic acid less effectively. How SLC17A5 gene variants affect sialin function depends on severity: milder variants may leave some transport activity, while more severe variants can greatly reduce or nearly stop it. This usually causes more cellular buildup and, in established SLC17A5-related conditions, can be linked to earlier or more marked features.
How variants are linked to conditions
Pathogenic variants in both copies of the SLC17A5 gene cause free sialic acid storage disease, a rare inherited condition that includes Salla disease and infantile free sialic acid storage disease. The link between the SLC17A5 gene and Salla disease is well established. Salla disease is usually the milder presentation, while the infantile form is associated with broader medical problems that begin early in life.
A variant is not necessarily a diagnosis
Genetic variants are a routine part of human biology and are widely seen in the general population. Most do not have a direct effect on health and instead reflect normal human diversity. For many genes, having a variant associated with a condition suggests a possible link rather than a certain diagnosis, especially when several genes and environmental factors also play a role. In other cases, though, one 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 SLC17A5, risk is mostly shaped by family history and whether both biological parents carry a changed copy of the gene. When both parents are carriers, each pregnancy has a 1 in 4 chance of the child having the condition. Risk is also higher in families with Finnish ancestry, where certain SLC17A5 changes are more common.
Inheritance of SLC17A5 variants
Variants in the SLC17A5 gene are inherited in an autosomal recessive pattern. This means a child must inherit one changed copy from each parent to have an SLC17A5-related condition, while parents with one changed copy are usually healthy carriers. When both parents carry an SLC17A5 gene variant, each pregnancy has a 25% chance of an affected child, a 50% chance of a carrier child, and a 25% chance of a child with two working copies. This is the established answer to how variants of the SLC17A5 gene are inherited.
What does my SLC17A5 result mean for my family?
Changes in the SLC17A5 gene linked to free sialic acid storage disease usually run in families in a recessive pattern. For family members, this mainly means brothers and sisters may also be affected or be carriers, and parents are usually carriers. Other close relatives may also carry the gene change, especially in families with a known history of the condition.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the SLC17A5 gene, a clinician can use SLC17A5 genetic testing with a blood, saliva, or cheek swab sample. The lab reads the gene’s DNA code and checks for changes that may help confirm or rule out a genetic cause of symptoms.
When should I consider getting a genetic test?
Consider SLC17A5 testing if a child has signs of this rare inherited condition, such as low muscle tone, developmental delay, trouble with movement, or other unexplained nerve and body symptoms. Testing can also help if there is a family history of an SLC17A5-related condition or if a relative is known to carry a harmful change in the gene.
A genetic result is only one part of your health story
Genetic findings can be informative, yet how much they explain depends on the specific condition and on the kind of variant present. Many factors also shape how the body works over time, 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 alongside other parts of care. In other situations, a genetic result can offer 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 affect how people respond to medicines. One person may break down a drug more slowly or more quickly than another, which can change how well the treatment works or how likely side effects are. These differences are common and are one reason the same medication can feel more helpful for some people and less helpful for others.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in a person’s genes affect the way medications work. By studying links between genes and drugs, it helps explain why the same treatment can have different effects in different people. For many medicines, genes influence both how powerfully 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 SLC17A5 gene
When should I seek medical advice?
This gene is not currently used in a broadly confirmed way to guide medication decisions, so any questions about side effects, new prescriptions, or changes in treatment are best discussed with your doctor or pharmacist.
History
Throughout history, people have described features that hinted at this gene. Salla disease was first recognized in Finland in the 1970s, when doctors noticed a distinct inherited condition affecting development and movement in children from the Salla region. Inheritance patterns were noticed long before the gene was identified. During the 1990s, researchers mapped the cause to chromosome 6 and then identified the SLC17A5 gene as the source of Salla disease and the related free sialic acid storage conditions. This work helped clarify that these conditions were part of the same disease spectrum rather than entirely separate illnesses. From these first observations, research expanded steadily, especially in Finland, where the condition had been studied most closely.