The AQP5 gene gives your body instructions for a water channel that helps move water through cells in the salivary glands, tear glands, sweat glands, and airways. This gene helps your body make and release fluids such as saliva, tears, sweat, and airway moisture. If it does not work as expected, you may have changes in these secretions, and some variants in the AQP5 gene are linked to thickened skin on the palms and soles.
What is a gene?
Genes are sections of DNA that carry instructions your cells use to make molecules or direct activities in the body. Some genes provide the code for proteins, which do much of the cell’s day to day work. Others are mainly involved in regulating when certain processes happen, where they happen, and how active they are. As a group, genes affect how the body grows and works, and they can also influence your response to food, stress, and medicines. More detail on this topic is available in the LearnHub.
Overview
AQP5Gene function
What if the gene works
The AQP5 gene helps move water through cells in the salivary, tear, and sweat glands. This supports normal saliva, tears, and sweat production and helps keep the mouth, eyes, and airways moist.
Risk
What if the gene does not work
Certain variants in the AQP5 gene can cause palmoplantar keratoderma, with thickened skin on the palms and soles, excess sweating, and strong wrinkling after water exposure. Effects may range from mild to more marked, depending on the variant.
Treatment
What does that mean for your treatment
For pathogenic or loss-of-function variants in the AQP5 gene, no treatment or management approach tied specifically to this gene is currently established in clinical guidelines. The AQP5 gene is being studied as a biomarker and possible drug target in salivary gland problems, lung disease, and some cancers, but this has not changed standard drug choices.
Conditions associated with AQP5
Gene function
What if the gene works
AQP5 helps your body move water in a controlled way across certain cell surfaces. This is especially important in glands and moist linings that need to release fluid. Understanding how the AQP5 gene works helps explain how your body keeps saliva, tears, and airway moisture balanced from day to day.
The AQP5 gene helps make a channel that lets water pass through cell membranes. This gives certain cells a fast, controlled way to move water when they are making or adjusting body fluids.
In salivary and tear glands, this channel helps water enter the fluid those glands release. This is a key part of how the AQP5 gene helps make saliva and tears for daily comfort.
This gene also supports water movement in the moist lining of the lungs and airways. Keeping this thin fluid layer balanced supports smooth airflow and lets mucus move more easily.
What is a variant?
A genetic variant is a minor difference in the DNA sequence of 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 variants do not have any noticeable effect and simply represent natural genetic variation. In some situations, though, a variant changes how a gene functions more markedly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
How AQP5 gene variants affect the protein depends on the exact DNA change. Some variants alter the channel’s shape, stability, movement to the cell surface, or how easily it opens, which can change water flow across cells. In AQP5-related palm and sole skin thickening, many disease-causing variants are missense changes that seem to disturb channel behavior rather than remove the protein completely. Milder variants may cause smaller functional changes, while more disruptive ones can be linked to earlier or more marked features.
How variants are linked to conditions
Pathogenic variants in the AQP5 gene are a well-established cause of palmoplantar keratoderma, a group of conditions that cause thickened skin on the palms and soles. AQP5 gene variants linked to palmoplantar keratoderma have been reported in Bothnian type and closely related forms. Some people also have white, swollen skin after water exposure and increased sweating of the hands and feet.
A variant is not necessarily a diagnosis
Genetic variants are common and are a normal part of human biology. Most do not have a direct effect on health and simply contribute to natural human diversity. For many genes, carrying a variant associated with a condition points to a possible link rather than a definite diagnosis, especially when several genes and environmental factors also play a role. In some situations, though, a single well-characterized variant in a specific 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 health risk related to the AQP5 gene. If an AQP5 change is found on genetic testing, overall risk can still vary from person to person, and a doctor or genetic counselor can help put that result in context.
Inheritance of AQP5 variants
AQP5-related palm and sole skin conditions are usually inherited in an autosomal dominant pattern. This means a person with a disease-causing variant in one copy of the AQP5 gene can pass it to a child, with a 50% chance in each pregnancy. Sons and daughters are affected and can inherit it equally because the AQP5 gene is on chromosome 12, not a sex chromosome. In practical terms, the AQP5 inheritance pattern often shows up across multiple generations of a family.
What does my AQP5 result mean for my family?
Some AQP5 changes are linked to an inherited skin condition that usually follows a dominant pattern, so close relatives such as a parent, brother, sister, or child may also carry the same change. For many families, this means each child of someone with the variant has a 1 in 2, or 50%, chance of inheriting it. Family members who have thickened skin on the palms or soles may especially want to review the result with their care team.
Genetic information
Genetic testing
How you find out about variants
Testing for variants in the AQP5 gene usually uses a blood sample, saliva, or a cheek swab. In genetic testing for AQP5 variants, a lab reads the DNA code to look for changes and reports whether a variant was found, which can help clarify whether this gene is involved.
When should I consider getting a genetic test?
There isn't yet a broadly established clinical reason to test specifically for changes in the AQP5 gene. Testing decisions are usually based on your symptoms, exam findings, and family history, and are best discussed with a doctor or genetic counselor.
A genetic result is only one part of your health story
A genetic result can be informative, but how much it explains varies by the condition and the type of variant involved. Over time, how your body works is also shaped by factors such as lifestyle, environment, age, and medical history. For some conditions, especially those influenced by many genes, genetic information provides context rather than certainty and is best considered alongside other parts of care. In other situations, a genetic result may offer a clear answer. In areas like medication response, genetic results can also help put individual 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 absorbs, breaks down, or responds to a drug, so the same treatment may work well for one person but less well for another. These differences are common and can influence both how helpful a medicine is and how sensitive someone may be to side effects.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences shape a person’s response to medications. It studies 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 affect both how the body processes a drug and how strong its effects are. This information can support more informed, individualized treatment decisions. You can read more about this topic in the LearnHub.
Drugs influenced by the AQP5 gene
When should I seek medical advice?
There is no broadly confirmed evidence that this gene should be used to predict how you will respond to medicines, so general concerns about your health, side effects, or treatment changes are best discussed with your doctor.
History
The AQP5 gene entered medical research during the rapid discovery of aquaporins in the 1990s, when scientists were identifying the body’s key water channel genes. Building on this early work, researchers linked the AQP5 gene to tissues that make saliva, tears, and lung secretions, which made it especially relevant to everyday symptoms such as dry mouth and dry eyes. Its discovery helped expand the aquaporin field beyond the first water channel genes and showed that different family members are active in different organs. In the years that followed, the AQP5 gene became part of research on gland function, airway health, and inherited differences in fluid balance. Over time, descriptions became more precise as genetic and laboratory studies clarified where this gene is active and why it drew clinical interest.