SRD5A3 helps your cells make and process certain fats needed to attach sugar chains to proteins, a step that supports normal brain, eye, and body development. If the SRD5A3 gene does not work properly, a person can have a rare inherited condition that may affect vision, balance, muscle tone, learning, and growth. Some people also have unusual eye movements, feeding difficulties, or liver findings. Understanding this gene can help clarify why these features appear together from early life.
What is a gene?
Genes are sections of DNA that give your cells instructions for making molecules or managing processes in the body. Some genes provide the directions for producing proteins, which are the parts of cells that carry out much of the work. Other genes are used mainly to regulate when certain processes happen, where they take place, and how strongly they run. As a group, genes affect how the body develops and functions, and they can also influence how you respond to food, stress, and medications. To look into this topic more closely, you can find more in the LearnHub.
Overview
SRD5A3Gene function
What if the gene works
The SRD5A3 gene helps cells make dolichol, which cells use to attach sugars to many proteins. This supports normal protein function across the body, including the brain, eyes, and skin.
Risk
What if the gene does not work
Variants in the SRD5A3 gene most often cause SRD5A3-congenital disorder of glycosylation, which can affect vision, brain development, movement, and skin. Effects range from milder learning and eye problems to earlier, more widespread symptoms.
Treatment
What does that mean for your treatment
No treatment or drug choice is currently guided specifically by pathogenic or loss-of-function variants in the SRD5A3 gene. Care is based on a person’s symptoms rather than a medicine targeted to this gene. Separately, the SRD5A3 gene is being studied in some cancers, especially prostate cancer, as a possible biomarker and treatment target.
Conditions associated with SRD5A3
Gene function
What if the gene works
Inside your cells, the SRD5A3 gene helps make a fatty molecule called dolichol. Cells use dolichol as a carrier when they add sugar chains to many newly made proteins. This helps explain what the SRD5A3 gene does in the body.
The SRD5A3 gene helps turn another fat-like molecule, called polyprenol, into dolichol. This gives cells an important building block for normal protein processing.
Dolichol made with help from the SRD5A3 gene lets cells attach sugar chains to many proteins. This process, called glycosylation (adding sugar chains), helps proteins fold and move to the right place.
By supporting normal glycosylation (adding sugar chains), this gene helps many proteins become ready for their jobs. That routine step supports steady cell work across many tissues.
What is a variant?
A genetic variant is a small difference in the DNA sequence within a gene. These differences are common and are part of normal human diversity, including variation in appearance, metabolism, and how the body responds to environmental influences. Many have no noticeable effect and simply represent natural genetic variation. In some situations, though, a variant changes how a gene works more substantially and can contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the SRD5A3 gene can reduce or block production of a protein needed to make dolichol, a fat-like molecule cells use to attach sugar chains to many proteins. This shows how SRD5A3 gene variants affect protein function: milder variants may leave some enzyme activity, while more severe variants can create a shortened or unstable protein with little or no activity. When dolichol drops, protein glycosylation (sugar attachment) is disrupted. Greater loss of activity often goes along with earlier and broader features of SRD5A3-congenital disorder of glycosylation.
How variants are linked to conditions
Pathogenic variants in the SRD5A3 gene cause SRD5A3-congenital disorder of glycosylation, a rare inherited condition that can affect several body systems. SRD5A3 gene variants are linked to developmental delay, intellectual disability, low muscle tone, balance or movement difficulties, and vision loss or other eye problems. Severity can vary widely from one person to another.
A variant is not necessarily a diagnosis
Genetic variants are a routine part of human biology and are common across the general population. Most have no direct impact on health and simply reflect natural human diversity. For many genes, carrying a variant associated with a condition suggests a possible link rather than a definite diagnosis, especially when more than one gene and environmental factors are involved. In some cases, though, one well-characterized variant in a specific gene can be enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For SRD5A3, risk is mainly shaped by inheritance rather than lifestyle. A child’s chance is higher when both parents carry a harmful SRD5A3 change, and this can be more likely in families where relatives have children together. There is not enough evidence to say that diet, exercise, or other daily habits lower this genetic risk.
Inheritance of SRD5A3 variants
SRD5A3-related conditions follow an autosomal recessive inheritance pattern, which explains how SRD5A3 gene variants are inherited in families. This means a child usually inherits one altered copy of the SRD5A3 gene from each parent. Parents who each carry one variant are often unaffected carriers, and with each pregnancy they have a 25% chance of having an affected child, a 50% chance of having a carrier child, and a 25% chance of having a child with two usual copies of the gene. Because the SRD5A3 gene is on an autosome rather than a sex chromosome, this inheritance pattern is the same for boys and girls.
What does my SRD5A3 result mean for my family?
For families with an SRD5A3-related condition, the pattern is usually recessive, which means parents are often healthy carriers and brothers or sisters may also be affected or be carriers. Full siblings may want to discuss family testing because the same gene change can run quietly through a family. Other relatives, such as aunts, uncles, and cousins, may also carry the change, especially on the same side of the family.
Genetic information
Genetic testing
How you find out about variants
To look for variants in the SRD5A3 gene, doctors use SRD5A3 genetic testing on a blood or saliva sample. A lab reads the gene’s DNA code to check for variants that may explain symptoms or confirm a suspected inherited condition. Results may show a variant linked to the condition, no relevant variant, or a finding that needs more interpretation.
When should I consider getting a genetic test?
Genetic testing for SRD5A3 may be worth considering when a child has a pattern of early symptoms such as developmental delay, vision problems, low muscle tone, or balance trouble, especially if similar issues run in the family. It can also help clarify the cause after other testing suggests a rare inherited condition affecting how the body builds and uses proteins.
A genetic result is only one part of your health story
Genetic results can provide useful insight, but how much they reveal depends on both the condition and the kind of variant involved. How the body works over time is also shaped by many factors, 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 understood together with other parts of care. In other situations, a genetic result can give a clear answer. In areas like medication response, these results may help place personal experiences in context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how a person responds to medicines. Small differences in genes can change how the body breaks down a drug, moves it through the body, or responds to it at its target. This helps explain why the same treatment works well for some people, works less well for others, or causes more side effects in some than in others.
What is Pharmacogenetics?
Pharmacogenetics focuses on how differences in genes can affect the way someone responds to a medication. It examines relationships 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 strongly a drug works and how the body handles it. This information can help support more informed, individualized treatment decisions. You can read more about this topic in the LearnHub.
Drugs influenced by the SRD5A3 gene
When should I seek medical advice?
There isn’t yet a broadly confirmed role for this gene in guiding medication choice or dose, so concerns about side effects, new symptoms, or how well a treatment is working are best discussed with your doctor.