The SLC38A8 gene helps the eyes develop normally, especially the fovea, the small central area of the retina that gives sharp detail vision. This gene plays an important role in guiding early visual development, and if it does not work properly, a person may be born with reduced central vision and involuntary eye movements called nystagmus. Some people with variants in the SLC38A8 gene also have eyes that do not line up fully or other differences in eye development.
What is a gene?
Genes are stretches of DNA that give cells instructions for making molecules or managing activities in the body. Some genes provide the code for proteins, which are the parts of cells that do much of the work. Others mainly guide 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 medications. For a deeper look at this topic, you can find more in the LearnHub.
Overview
SLC38A8Gene function
What if the gene works
The SLC38A8 gene helps move certain amino acids into cells, especially in the retina and brain. This supports normal eye development and the work of nerve cells.
Risk
What if the gene does not work
Variants in the SLC38A8 gene can disrupt development of the retina's center and visual pathways, causing foveal hypoplasia, involuntary eye movements, and reduced vision. Milder and more severe variants can influence when signs appear and how much vision is affected.
Treatment
What does that mean for your treatment
No SLC38A8-specific treatment or drug choice is currently established; care is supportive and guided by a person’s vision needs rather than a targeted therapy for the SLC38A8 gene.
Conditions associated with SLC38A8
Gene function
What if the gene works
Your cells need a steady supply of amino acids to build proteins and stay balanced. The SLC38A8 gene helps move some of these nutrients across the cell membrane, especially in nerve tissues such as the retina. Understanding SLC38A8 gene function is easiest when you picture it as part of your cells’ nutrient transport system.
SLC38A8 helps carry certain amino acids into cells through the cell membrane. This gives cells a regular supply of small building blocks they use for everyday work.
Its transport process uses sodium moving with the amino acid to help bring nutrients into the cell. This lets cells take in useful molecules in a controlled way.
By helping amino acids enter cells, this gene supports normal internal balance and routine cell activity. That steady supply helps cells manage daily needs across the tissues where SLC38A8 is active.
What is a variant?
A genetic variant is a minor change in the DNA sequence of a gene. These changes are common and help shape normal human diversity, such as 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 cases, 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 SLC38A8 gene can alter the transporter protein’s shape, making it unstable, trapping it inside the cell, or reducing its transport activity. This pattern helps explain how variants in the SLC38A8 gene affect eye development: more disruptive variants may leave little or no activity, while milder variants may preserve some. Less remaining activity is linked to stronger effects on the center of the retina and visual pathway wiring in SLC38A8-related conditions.
How variants are linked to conditions
Pathogenic variants in the SLC38A8 gene cause SLC38A8-related foveal hypoplasia, often called FHONDA syndrome. This rare inherited eye condition is linked to reduced visual sharpness from birth and involuntary eye movements called nystagmus. Some people also have other eye findings, including changes in the front part of the eye. A disease-causing variant in both copies of the gene can confirm the diagnosis.
A variant is not necessarily a diagnosis
Variants in genes are a usual part of human biology and are widely found across the general population. Most do not directly affect health and instead reflect natural human diversity. For many genes, having a variant associated with a condition points to a possible link rather than a definite diagnosis, especially when multiple genes and environmental factors also play a role. In some situations, though, 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 SLC38A8, risk is mainly set by genetics rather than lifestyle. A child’s chance of having the related eye condition is higher when both biological parents carry a disease-causing change in the SLC38A8 gene. There is not enough evidence to say that diet, exercise, or other everyday habits lower this risk.
Inheritance of SLC38A8 variants
In families with SLC38A8-related foveal hypoplasia, the SLC38A8 inheritance pattern is autosomal recessive. This means a child usually inherits one altered copy of the SLC38A8 gene from each parent. Parents who each carry one variant are often unaffected, and 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.
What does my SLC38A8 result mean for my family?
For families with an SLC38A8-related condition, parents are usually healthy carriers of the gene change. Brothers and sisters may also have the condition or be carriers, even if they do not have obvious eye problems. Close relatives on both sides of the family may also carry the same gene change, so the result can matter beyond one person.
Genetic information
Genetic testing
How you find out about variants
To look for changes in this gene, doctors use genetic testing for SLC38A8 variants on a blood or saliva sample. A laboratory reads the SLC38A8 gene to check for variants, and the result may show a pathogenic variant, no relevant variant, or a finding that needs expert interpretation.
When should I consider getting a genetic test?
Genetic testing for the SLC38A8 gene may be worth considering when someone is born with shaky eyes, reduced vision, or underdevelopment of the center of the retina, especially if albinism tests are negative. It can also help explain a family history of these eye findings.
A genetic result is only one part of your health story
Genetic results can provide useful insight, but how much they reveal depends on the condition and on the kind of variant involved. Over time, many factors also shape how the body works, including lifestyle, environment, age, and medical history. For some conditions, especially those influenced by many genes, genetic information offers context rather than certainty and is best viewed alongside other parts of care. In other situations, a genetic result may give a clear answer. In areas such as 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. A treatment that works well for one person may work less well for another, or may cause more side effects, because the body can absorb, break down, transport, or react to a drug in different ways. These inherited differences are common and can influence how strongly a medicine works or how sensitive someone is to it.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in a person’s genes affect the way they respond to medicines. It studies gene-drug patterns to help explain why the same treatment can work differently in different people. For many drugs, genes influence how powerfully a medicine works or how the body handles it. This information can support more informed, personalized treatment choices. More detail on this topic is available in the LearnHub.
Drugs influenced by the SLC38A8 gene
When should I seek medical advice?
There is no broadly confirmed evidence that changes in this gene should guide medicine choices at this time, so questions about side effects, new symptoms, or how well a treatment is working are best discussed with your doctor.