The DENND5A gene helps cells move materials between their inner compartments, a job that is especially important during brain development. When both copies of this gene do not work properly, a child may have a genetic condition marked by developmental delay, low muscle tone, seizures, and changes in brain growth that doctors can see on brain scans. This gene plays an important role in helping nerve cells grow, connect, and work together.
What is a gene?
A gene is a stretch of DNA that carries instructions cells use to make molecules or regulate activities in the body. Some genes provide the directions for producing proteins, which are the functional components of cells. Others are involved mainly in controlling when specific processes happen, where they happen, and how active they are. Taken together, genes affect how the body grows and works, and they can also influence how you respond to food, stress, and medications. For a deeper look at this subject, you can find more in the LearnHub.
Overview
DENND5AGene function
What if the gene works
The DENND5A gene helps cells move proteins and other cargo between internal compartments. This trafficking supports normal cell organization and is especially important in the developing brain.
Risk
What if the gene does not work
More disruptive variants in the DENND5A gene are linked to a neurodevelopmental condition with delayed motor and language skills, low muscle tone, and brain imaging changes; some children have seizures. Milder variants may lead to later onset or fewer features.
Treatment
What does that mean for your treatment
No DENND5A-specific treatment or management approach is currently established, so drug and care choices are guided by a person’s symptoms rather than by the DENND5A gene itself.
Gene function
What if the gene works
Cells are always moving tiny packages of proteins and membrane from one place to another. The DENND5A gene supports this internal delivery network so cargo reaches the right location on time. A simple way to understand how the DENND5A gene helps cells move proteins is to picture an organized shipping system inside each cell.
The DENND5A gene helps direct vesicles (small membrane packages) as they travel inside the cell. This lets proteins and other materials reach the correct compartment instead of drifting to the wrong place.
Much of this work happens near the Golgi apparatus (the cell's shipping center), where cargo is sorted for delivery. DENND5A helps keep that sorting and dispatch process orderly.
Inside cells, DENND5A works with transport-control proteins that tell vesicles when to form, move, and dock. That coordination supports steady day to day cell activity and organized cell growth.
What is a variant?
A genetic variant is a minor change in the DNA sequence within a gene. These changes are common and form part of normal human diversity, including differences in appearance, metabolism, and how the body responds to environmental influences. Many variants do not cause any noticeable effect and simply represent natural genetic variation. In some situations, though, a variant can change how a gene works more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the DENND5A gene can alter the DENND5A protein’s shape, stability, or ability to interact with other cell parts, so the protein may be made in low amounts or not work well. More disruptive changes, such as variants that shorten the protein, often have a larger effect than missense variants that change a single building block. In DENND5A gene variants, this loss of function can range from partial to near complete, and more severe loss is often linked with earlier and more pronounced brain-related features.
How variants are linked to conditions
Pathogenic variants in the DENND5A gene cause a rare inherited condition often called developmental and epileptic encephalopathy 49. Many people with a DENND5A gene variant have developmental delay, low muscle tone, feeding problems, and seizures, and brain scans may show enlarged fluid spaces or other changes. Features vary from person to person, so the diagnosis helps explain the pattern of symptoms rather than predict exactly how someone will be affected.
A variant is not necessarily a diagnosis
Genetic variants are a routine feature of human biology and are found throughout 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 points to a possible link rather than a certain diagnosis, particularly when more than one gene and environmental influences play a role. In other situations, though, one well characterized variant in a particular gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For DENND5A, risk is mainly set by genetics rather than lifestyle. A child’s chance of having a DENND5A-related condition is higher when both biological parents carry a disease-causing change in the DENND5A gene, especially in families with a known history of the condition. There is not enough evidence to say that diet, exercise, or other daily habits change this risk.
Inheritance of DENND5A variants
DENND5A-related conditions are inherited in an autosomal recessive pattern. This means a child usually inherits one DENND5A gene variant from each parent, and both parents are typically healthy carriers. When both parents carry a variant in the DENND5A gene, each pregnancy has a 25% chance of resulting in a child with the condition, a 50% chance of producing a carrier child, and a 25% chance of producing a child with no familial variant. For families looking into how DENND5A variants are inherited, this pattern applies equally to boys and girls.
What does my DENND5A result mean for my family?
For families with a disease-causing DENND5A result linked to a recognized DENND5A-related condition, this usually means the condition runs in a recessive pattern. Parents are often healthy carriers, and brothers or sisters may also be affected or may be carriers. Other close relatives, such as aunts, uncles, and cousins, may also carry the family variant.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the DENND5A gene, doctors use genetic testing for DENND5A variants on a blood or saliva sample. The lab reads the gene’s DNA sequence to look for changes, which can help confirm a genetic diagnosis in an affected person or clarify whether relatives carry the same variant.
When should I consider getting a genetic test?
If a child has major delays in sitting, talking, or walking, seizures, weak muscle tone, or brain scan changes, testing that includes the DENND5A gene may help find a cause. It can also be useful when a sibling has a DENND5A-related condition or there is a known family variant.
A genetic result is only one part of your health story
Genetic results can provide meaningful insight, but how much they reveal depends on the condition and the type of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, influence how the body works. For some conditions, especially those shaped by many genes, genetic information provides context rather than certainty and is most useful when viewed alongside other parts of care. In other situations, a genetic result may offer a clear answer. In areas such as 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. Small differences in genes can change how the body breaks down a drug, moves it through the body, or responds to its effects at the target tissue. This helps explain why the same medication works well for one person, seems weaker in another, or causes more side effects in someone else. These differences are common and are one reason treatment response is not the same for everyone.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in a person’s genes affect the way they respond to medicines. By studying the links between genes and medications, it helps explain why the same treatment can work differently in different people. With many drugs, genes can influence how strongly a medicine works or how the body handles it. This information can support treatment choices that are more informed and more tailored to the individual. More details on this topic are available in the LearnHub.
Drugs influenced by the DENND5A gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding how medicines are chosen or used, so general questions about side effects, new symptoms, or whether a treatment is right for you are best discussed with your doctor.
History
DENND5A entered the scientific literature through cell biology studies that examined proteins involved in moving materials inside cells. It was first described under earlier naming systems, including RAB6IP1, before DENND5A became the standard gene name. From these first observations, research expanded steadily. Over time, genetic sequencing made it possible to connect rare DENND5A variants with a neurodevelopmental condition marked by early brain development differences, delayed development, and seizures. That link, reported in the early 2020s, gave the gene clearer clinical importance and helped families receive a more specific genetic explanation.