The ALDH1A3 gene helps make retinoic acid, a signal your body uses to guide early growth, especially in the eyes and brain. This gene plays an important role in helping tissues form in the right place at the right time. When both copies of the gene do not work properly, a baby may be born with very small eyes or absent eyes, and some also have differences in brain development or learning. ALDH1A3 is mainly known in medical genetics rather than popular culture.
What is a gene?
A gene is a stretch of DNA that holds instructions your cells use to make molecules or regulate activities in the body. Some genes provide the code for proteins, which do much of the cell’s day to day work. Others mainly help control when certain processes happen, where they happen, and how active they are. Together, genes affect how the body develops and works, and they can also influence how you respond to food, stress, or medicines. You can find more detailed information in the LearnHub.
Overview
ALDH1A3Gene function
What if the gene works
The ALDH1A3 gene helps your body make retinoic acid, a signal made from vitamin A. This supports normal development of the eyes and parts of the brain before birth.
Risk
What if the gene does not work
Variants in the ALDH1A3 gene most often affect early eye development, causing a range from milder small eyes to absent eyes, sometimes with additional brain or developmental differences. More disruptive variants often lead to earlier and broader effects.
Treatment
What does that mean for your treatment
No ALDH1A3-specific treatment or management approach is currently established. Care is supportive and based on the person’s symptoms, rather than on a drug chosen for a pathogenic variant in the ALDH1A3 gene. The ALDH1A3 gene is also being studied as a possible biomarker and drug target in some cancers, but this has not led to routine gene-directed treatment for inherited ALDH1A3-related conditions.
Conditions associated with ALDH1A3
Gene function
What if the gene works
During early growth, your body needs clear chemical signals to guide how cells develop and organize. A key part of ALDH1A3 gene function is helping cells make retinoic acid, a signal derived from vitamin A. This signal supports normal gene activity and cell specialization in many developing tissues.
ALDH1A3 helps cells change retinal, a form of vitamin A, into retinoic acid. Retinoic acid acts as a messenger that tells cells how to grow and organize.
The retinoic acid made through ALDH1A3 helps switch certain genes on or off at the right time. This keeps developmental instructions coordinated as tissues take shape.
By supplying retinoic acid, ALDH1A3 helps immature cells move toward specialized roles. This supports orderly development in tissues that need precise early signals.
What is a variant?
A genetic variant is a minor change in a gene’s DNA sequence. These changes are common and help shape normal human diversity, including differences in appearance, metabolism, and the way the body responds to environmental influences. Many variants do not have any noticeable effect and are simply part of natural genetic variation. Sometimes, though, a variant changes how a gene works to a greater extent and can contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the ALDH1A3 gene can reduce enzyme activity, make the protein unstable, or prevent it from folding into the right shape, which lowers retinoic acid production during early eye development. Some ALDH1A3 gene variants are milder and leave partial activity, while more severe variants may stop the enzyme from working almost completely. This range in functional effect can influence how early eye differences appear and how marked they are, including very small eyes or absent eye tissue in some people.
How variants are linked to conditions
Pathogenic variants in the ALDH1A3 gene are a known cause of rare eye conditions present from birth, especially autosomal recessive microphthalmia and anophthalmia. In everyday terms, ALDH1A3 gene variants can lead to one or both eyes being unusually small or absent, often with marked vision loss. Some people also have related structural eye differences, including coloboma.
A variant is not necessarily a diagnosis
Genetic variants are a routine part of human biology and are widespread across the population. Most do not directly affect health and instead reflect normal human diversity. For many genes, having a variant tied to a condition points to a possible link, not a certain diagnosis, particularly when several genes and environmental factors play a role. In some situations, though, one well described variant in a particular gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
There isn't yet broadly confirmed evidence on specific factors that increase or reduce risk related to ALDH1A3. In families with disease-causing changes in both copies of this gene, the chance of the eye condition is mainly shaped by the genetic changes themselves, and a doctor or genetic counselor can help explain personal and family risk.
Inheritance of ALDH1A3 variants
ALDH1A3-related conditions are inherited in an autosomal recessive pattern. This means a child usually inherits one ALDH1A3 gene variant from each parent, and parents who carry one variant are typically unaffected carriers. When both parents are carriers, each pregnancy has a 25% chance of the child inheriting both variants, a 50% chance of being a carrier, and a 25% chance of inheriting neither variant. In practical terms, how ALDH1A3 variants are inherited depends on both copies of this gene being changed.
What does my ALDH1A3 result mean for my family?
For ALDH1A3, family implications are usually based on a recessive pattern linked to severe eye development conditions present from birth. Parents of an affected child are often healthy carriers, and brothers or sisters may also be affected or be carriers. Other relatives, such as adult siblings, may want to learn whether they carry the family variant, especially if they are planning children.
Genetic information
Genetic testing
How you find out about variants
Testing for variants in the ALDH1A3 gene usually starts with a blood or saliva sample. ALDH1A3 genetic testing reads the gene's DNA code to look for changes that may help explain a person's condition or confirm a suspected inherited diagnosis. Results are interpreted alongside symptoms and family history.
When should I consider getting a genetic test?
Consider genetic testing for ALDH1A3 if a baby or child is born with very small eyes, absent eyes, or related eye development problems, especially if these run in the family. Testing can help confirm whether an ALDH1A3 change is the cause and clarify chances for future pregnancies.
A genetic result is only one part of your health story
A genetic result can provide useful information, but how much it explains depends on the condition and the type of variant. Over time, many other factors also shape how the body works, including lifestyle, environment, age, and medical history. For some conditions, especially those affected by many genes, genetic information provides 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 such as medication response, genetic results can also help put personal experiences into context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Small differences in DNA can change how the body breaks down a drug, moves it through the bloodstream, or responds at the target the drug is meant to affect. This helps explain why the same medication may work well for one person, seem less effective for another, or cause more side effects in someone else.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can shape a person’s response to medications. It studies connections between genes and drugs to help explain why the same treatment may work differently from one person to another. For many medicines, genes can affect both how strongly a drug works and how the body processes it. This understanding can help support more informed, individualized treatment decisions. More information on this topic is available in the LearnHub.
Drugs influenced by the ALDH1A3 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication choices. If you have questions about a medicine, side effects, or how treatment may affect you, talk with your doctor or pharmacist.