The ALDH18A1 gene helps your body make amino acids that support growth, skin strength, and healthy nerve function. If it does not work properly, you may have loose skin, cataracts, developmental delay, or increasing stiffness and weakness in the legs. Some variants cause symptoms in infancy, while others are linked to hereditary spastic paraplegia that appears later in life. Most variants in this gene have little effect, but a pathogenic variant can help explain a confirmed ALDH18A1 related condition.
What is a gene?
Genes act together to influence how the body develops and works, and they can also affect how you respond to food, stress, or medications. Each gene is a section 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 molecules that do much of the cell’s work. Other genes mainly control when certain processes happen, where they happen, and how strongly they take place. To go into this topic in more detail, you can read more in the LearnHub.
Overview
ALDH18A1Gene function
What if the gene works
The ALDH18A1 gene helps cells make proline, ornithine, and arginine from glutamate. This supports growth, connective tissue, and the body’s handling of nitrogen waste.
Risk
What if the gene does not work
Variants in the ALDH18A1 gene can affect nerves, skin, and eyes. Milder variants may mainly cause leg stiffness and weakness, while more severe variants can lead to problems starting in childhood with movement, development, loose skin, and cataracts.
Treatment
What does that mean for your treatment
No ALDH18A1-specific treatment or drug selection approach is currently established for people with pathogenic variants in the ALDH18A1 gene. Care is guided by symptoms rather than a gene-directed medicine, and ALDH18A1 is also being studied in early-stage metabolic and cancer research as a possible biomarker and drug target.
Conditions associated with ALDH18A1
Gene function
What if the gene works
The ALDH18A1 gene helps your cells make certain amino acid building blocks from glutamate, a common nutrient your body uses in many pathways. Its work happens mainly in mitochondria, where cells handle energy and basic chemistry. In simple terms, what the ALDH18A1 gene does in the body is support the first steps needed to make proline and help feed the pathway for ornithine.
The ALDH18A1 gene helps cells turn glutamate into an early ingredient for proline. Proline is an amino acid your body uses to build many proteins, including ones that support connective tissue.
That same early ingredient also feeds the pathway that makes ornithine, which can then contribute to citrulline and arginine. These amino acids support normal protein use and nitrogen handling.
Inside mitochondria, its protein carries out two connected chemical steps in sequence. Keeping both steps together helps cells move this pathway along in a steady, efficient way.
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 differences, such as appearance, metabolism, or the way the body responds to environmental influences. Many variants do not cause any noticeable effect and are simply part of natural genetic variation. Sometimes, though, a variant changes how a gene works more significantly and can contribute to or lead to a genetic condition.
Genetic variants
What if the gene does not work
Variants in the ALDH18A1 gene can change the shape or stability of the enzyme it makes, leaving cells with less activity or none at all. This shows how variants in the ALDH18A1 gene affect protein function. Some variants leave partial activity, while more severe variants can almost completely block the enzyme or disrupt how its two working parts interact. That difference may influence how early related features appear and how marked they are.
How variants are linked to conditions
Pathogenic variants in the ALDH18A1 gene cause inherited forms of hereditary spastic paraplegia, especially SPG9A and SPG9B, which often bring gradually increasing leg stiffness and walking problems. Some ALDH18A1 gene variants also cause cutis laxa and related conditions, sometimes alongside cataracts, growth concerns, or developmental differences. These are rare inherited conditions, and the specific features can vary from one person or family to another.
A variant is not necessarily a diagnosis
Genetic variants are a usual feature of human biology and are widespread in the general population. Most do not directly affect health and instead reflect normal human variation. For many genes, having a variant associated with a condition suggests a possible link rather than a definite diagnosis, especially when several genes and environmental factors also play a role. In some situations, 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?
There is not yet broadly confirmed evidence that specific lifestyle or environmental factors increase or reduce health risks related to the ALDH18A1 gene. Risk is mainly shaped by the genetic change itself and whether it runs in a family, so personal risk questions are best discussed with a doctor or genetic counselor.
Inheritance of ALDH18A1 variants
The inheritance of ALDH18A1-related conditions can differ depending on the specific condition and variant. Some ALDH18A1 gene conditions follow an autosomal dominant pattern, so a parent carrying the variant can pass it to a child of any sex with a 50% chance in each pregnancy. Other conditions linked to the ALDH18A1 gene follow an autosomal recessive pattern, which means a child usually inherits one variant from each parent, while carrier parents are often unaffected. This means how ALDH18A1 is inherited in families depends on the exact condition being considered.
What does my ALDH18A1 result mean for my family?
An ALDH18A1 result can have different family implications because this gene is linked to both dominant and recessive conditions. In some families, a parent with the same gene change may also have symptoms and close relatives could carry it too; in others, parents may be healthy carriers, and brothers or sisters could also be affected or be carriers. What it means for relatives depends on the exact ALDH18A1 change and the condition linked to it.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the ALDH18A1 gene, doctors use genetic testing for ALDH18A1 variants. A lab reads DNA from a blood or saliva sample and checks the gene for changes. Results may show no variant, a benign variant, or a variant linked to an ALDH18A1 condition.
When should I consider getting a genetic test?
Testing for changes in the ALDH18A1 gene may be considered when a child or adult has a pattern such as loose or wrinkly skin from birth, muscle stiffness or walking problems, delayed development, or a family history of the same features. It can help confirm whether an ALDH18A1-related condition is the cause.
A genetic result is only one part of your health story
A genetic finding can provide useful insight, but how much it explains depends on the condition and the kind of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, affect how the body functions. For some conditions, particularly those shaped by many genes, genetic information offers context rather than certainty and makes the most sense when viewed alongside other parts of care. In other situations, a genetic result can give a clear answer. For topics like medication response, genetic results can also help put a person’s experience in context.
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, so the same treatment can lead to different benefits or side effects. This is a common reason why a medication that works well for one person may feel too strong, not strong enough, or less predictable for someone else.
What is Pharmacogenetics?
Pharmacogenetics is the area of study focused on how genetic differences affect the way people respond to medications. It examines links between genes and drugs to help explain why the same treatment may work differently from one person to another. For many medicines, genes can influence both how the body handles a drug and how strongly it works. This information can support more informed, more individualized treatment decisions. You can read more about this topic in the LearnHub.
Drugs influenced by the ALDH18A1 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medicine choice or dose, so if you have side effects, a medicine is not working as expected, or you are starting a new treatment, the best next step is to discuss it with your doctor.
History
In recent decades, awareness of this gene’s role has grown. The ALDH18A1 gene entered the medical literature through research on inherited metabolic conditions and on how the body makes certain amino acids, the building blocks of proteins. Building on this early work, scientists linked variants in the ALDH18A1 gene to rare inherited conditions affecting development, movement, and connective tissues. As genetic testing became more widely used, doctors recognized that changes in this gene could appear in both childhood and adult-onset conditions. Over time, descriptions became more precise, and researchers learned that different variants in the same gene can be associated with a range of features. These historical steps shaped today’s understanding of the ALDH18A1 gene in clinical genetics.