The EXPH5 gene helps skin cells move and place small packets of material where they are needed to keep the outer layer of skin stable. When this gene does not work properly, the skin can become fragile and may blister or wear away after rubbing or minor injury. Pathogenic variants in the EXPH5 gene are linked to a form of epidermolysis bullosa simplex, a condition that mainly affects the skin. Some people also have areas of raw skin at birth or changes in the nails.
What is a gene?
Genes are sections of DNA that carry instructions your cells use to make molecules or regulate activities in the body. Some genes provide the directions for making proteins, which do much of the work inside cells. Other genes mainly help determine when certain processes happen, where they take place, and how active they are. Together, genes affect how the body develops and works, and they can influence how you respond to food, stress, and medications. For a deeper look at this topic, you can read more in the LearnHub.
Overview
EXPH5Gene function
What if the gene works
The EXPH5 gene helps skin cells move small cargo packages to the right place. This supports cell structure and helps the outer skin layer stay strong.
Risk
What if the gene does not work
Variants in the EXPH5 gene are linked to epidermolysis bullosa simplex, with fragile skin and blisters after minor rubbing. Effects can range from milder to more severe, often starting in infancy or childhood.
Treatment
What does that mean for your treatment
At present, no EXPH5-specific treatment or drug selection approach is established for people with a pathogenic variant in the EXPH5 gene; care is guided by the person’s symptoms and supportive skin management rather than by the variant itself.
Conditions associated with EXPH5
Gene function
What if the gene works
Inside your cells, the EXPH5 gene helps move tiny membrane wrapped packages to the places where they are needed. This is especially important in skin cells, where steady delivery to the cell surface supports routine upkeep. In simple terms, this is how the EXPH5 gene helps skin cells move cargo to the cell surface in an orderly way.
The EXPH5 gene helps guide small vesicles, which are tiny sacs that carry proteins and other materials inside cells. It supports the cell's transport system so cargo reaches the right area at the right time.
EXPH5 works with Rab27 helper proteins that direct vesicles toward the cell membrane. This supports exocytosis (the step where a cell adds material to its surface or releases it outside).
By placing vesicles where they are needed, EXPH5 supports orderly cell structure and normal surface renewal. In skin cells, this helps everyday maintenance stay coordinated.
What is a variant?
A genetic variant is a minor difference in the DNA sequence of a gene. These differences are common and help shape normal human diversity, including variation in appearance, metabolism, and how the body responds to environmental influences. Many variants do not lead to any noticeable effect and are simply part of natural genetic variation. Sometimes, 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
Changes in the EXPH5 gene usually reduce or eliminate the exophilin-5 protein, which disrupts intracellular transport in skin cells and weakens their stability under friction. In many people, how EXPH5 gene variants affect protein function depends on the type of DNA change: truncating variants often leave little or no working protein, while some missense variants may preserve partial activity. This spectrum can shape how early skin blistering begins and how pronounced it is.
How variants are linked to conditions
Pathogenic variants in the EXPH5 gene can cause epidermolysis bullosa simplex, an inherited skin condition with fragile skin, easy blistering, and small skin wounds after minor friction. This form of epidermolysis bullosa simplex linked to the EXPH5 gene often begins at birth or in early infancy, although severity varies between people. A confirmed disease-causing variant in the EXPH5 gene can establish the genetic diagnosis.
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 simply reflect normal human diversity. For many genes, having a variant associated with a condition points to a possible link rather than a certain diagnosis, particularly when several genes and environmental influences play a part. In some situations, though, one well understood variant in a particular gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
There is not yet broadly confirmed evidence on specific factors that increase or reduce health risks related to the EXPH5 gene. In families with an EXPH5-related skin condition, risk is mainly shaped by the gene changes inherited rather than lifestyle, and anyone concerned about personal or family risk can talk with a doctor or genetic counselor.
Inheritance of EXPH5 variants
EXPH5-related skin fragility conditions are inherited in an autosomal recessive pattern. This means a person usually develops the condition only when they inherit two disease-causing EXPH5 gene variants, one from each parent. Parents who each carry one EXPH5 gene variant are typically unaffected carriers, and with each pregnancy they have a 25% chance of having an affected child, a 50% chance of having a child who is a carrier, and a 25% chance of having a child without the familial variants. In practical terms, how EXPH5 gene variants are inherited often becomes clear when an affected child is born to two healthy carrier parents.
What does my EXPH5 result mean for my family?
For families with an EXPH5-related skin condition, the pattern is usually recessive, which means close relatives may be healthy carriers without knowing it. Brothers and sisters could also be affected or be carriers, and other blood relatives may carry the same gene change. This can be useful information for family planning and for relatives who want to learn whether the change runs in the family.
Genetic information
Genetic testing
How you find out about variants
EXPH5 genetic testing looks for changes in your DNA using a blood sample, saliva, or a cheek swab. A lab reads the EXPH5 gene to check for variants that may help explain inherited skin fragility and can confirm whether a known family variant is present. Results may show a disease causing variant, no relevant variant, or an uncertain finding.
When should I consider getting a genetic test?
If there is a history of very fragile skin, repeated blisters after minor rubbing, or a family history of an inherited blistering skin condition, testing for changes in the EXPH5 gene may help clarify the cause. It can also be useful when a child is born with unexplained skin blistering.
A genetic result is only one part of your health story
Genetic findings can provide useful insight, yet how much they reveal varies by the condition and the type of variant involved. Many factors also shape how the body works over time, including age, lifestyle, environment, 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 such as medication response, these results may help place personal experiences in context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how your body handles medicines, so the same treatment may work differently from one person to another. Some people process a drug faster or slower, while others are more or less sensitive to its effects. These common differences can influence how well a medicine works and the chance of side effects.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences affect the way a person responds to medications. It looks at gene-drug patterns to better understand why the same treatment may work differently from one person to another. For many medicines, genes influence how strongly a drug works or how the body handles it. This information can support treatment decisions that are more informed and more individualized. You can read more about this topic in the LearnHub.
Drugs influenced by the EXPH5 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in predicting how medicines will work, so questions about symptoms, treatment, or side effects are best discussed with your doctor or pharmacist.
History
EXPH5 entered medical genetics more recently than many better-known genes, through work on inherited skin fragility conditions. In recent decades, awareness of this gene’s role has grown as researchers linked EXPH5 variants to a form of epidermolysis bullosa simplex, a condition that can cause skin blistering after minor friction. Early reports connected affected families with shared clinical features, and later genetic studies identified EXPH5 as the cause in some of them. From these first observations, research expanded steadily and helped define where EXPH5 fit within the growing list of genes involved in inherited blistering conditions. That work gave doctors and families a clearer genetic label for cases that had previously been harder to classify.