The APRT gene helps your body recycle adenine, a building block released during normal cell breakdown, into a form your cells can reuse. If the APRT gene does not work properly, adenine can be changed into 2,8-dihydroxyadenine, a substance that does not dissolve well in urine. This can lead to repeated kidney stones, crystals in the urine, and over time kidney injury. Learning about this gene can clarify why some genetic results point to a treatable inherited cause of kidney stones.
What is a gene?
Genes are stretches of DNA that carry instructions your cells use to make molecules or regulate processes in the body. Some genes provide the instructions for producing proteins, the parts of cells that do the work. Other genes mainly help determine when certain processes happen, where they occur, and how strongly they operate. Together, genes affect how the body develops and functions, and they can influence how you respond to food, stress, or medications. For a more in depth look at this topic, you can learn more in the LearnHub.
Overview
APRTGene function
What if the gene works
The APRT gene helps recycle adenine, a building block of DNA and energy molecules, into a usable form. This helps keep the body's adenine levels balanced and reduces waste that could otherwise build up.
Risk
What if the gene does not work
People with two nonworking variants in the APRT gene can develop APRT deficiency, causing 2,8-dihydroxyadenine kidney stones and sometimes kidney damage. Milder and more severe variants can influence when symptoms begin and how much the kidneys are affected.
Treatment
What does that mean for your treatment
With pathogenic variants in the APRT gene, allopurinol is commonly used, and febuxostat can be used if allopurinol is not suitable. These medicines block production of the substance that causes crystal and stone buildup in APRT deficiency and can help protect kidney function. High fluid intake and a diet lower in purines may be added, while making the urine more alkaline does not help.
Conditions associated with APRT
Gene function
What if the gene works
Your cells constantly reuse small chemical parts instead of making everything from scratch. The APRT gene supports that recycling by helping turn free adenine into a form cells can use again. Understanding how the APRT gene helps recycle adenine in the body makes it easier to see how cells keep a steady supply of basic building material.
APRT helps your cells capture adenine, one of the parts used to make DNA and RNA. It converts adenine into AMP, a usable form the cell can put back to work.
This recycling step helps keep the cell’s purine building blocks in balance. That supports steady day to day cell activity and avoids wasting energy on making more material than needed.
Reusing adenine gives your cells an efficient shortcut. It helps many tissues maintain routine growth and renewal without having to make the same building block from the beginning.
What is a variant?
A genetic variant is a small 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 have any noticeable effect and are simply part of natural genetic variation. In some cases, 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
Variants in the APRT gene can reduce or abolish adenine phosphoribosyltransferase activity, causing adenine to be diverted into 2,8-dihydroxyadenine, which does not dissolve well and can form crystals. The cellular effects of APRT gene variants often come from changes that distort the enzyme’s shape, make it unstable, or create a shortened protein with little or no activity. Milder variants may leave some activity, while more severe variants can lead to earlier or more persistent crystal buildup and kidney stones.
How variants are linked to conditions
Pathogenic variants in the APRT gene cause APRT deficiency, an inherited condition that can lead to recurrent kidney stones and crystal buildup in the kidneys. This is the main link described between APRT gene variants and kidney stones. In people with two disease-causing variants, reduced kidney function or chronic kidney disease can also develop, especially if the condition is not recognized.
A variant is not necessarily a diagnosis
Variants in genes are a normal feature of human biology, and they are common across the general population. Most do not directly affect health and simply reflect natural differences among people. For many genes, carrying a variant associated with a condition suggests a possible link rather than a certain diagnosis, especially when more than one gene and environmental factors play a role. In some situations, though, a single well-understood variant in a particular gene can be enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For APRT, risk is mainly set by genetics: people usually develop the condition only if they inherit two changed copies of the APRT gene, one from each parent. In people living with APRT deficiency, low fluid intake or dehydration can raise the chance of kidney stones and kidney damage.
Inheritance of APRT variants
APRT-related disease is inherited in an autosomal recessive pattern. This means a person usually develops APRT deficiency only when they inherit two disease-causing variants in the APRT gene, one from each parent. Parents who carry one variant are typically carriers and usually do not have the condition. For families looking into APRT gene inheritance, each pregnancy between two carriers has a 25% chance of an affected child, a 50% chance of a carrier child, and a 25% chance of a child with no familial variant.
What does my APRT result mean for my family?
APRT-related kidney stone disease usually runs in families in a recessive pattern, so brothers and sisters may also have the condition or carry the same gene change even if they feel well. Parents are usually healthy carriers, and other close relatives may be carriers too. In families with a known APRT result, relatives may want to discuss whether their own results could help explain kidney stones or kidney problems.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for APRT gene variants uses a blood, saliva, or cheek swab sample to read your DNA and look for changes in the APRT gene. It can show whether you carry a variant linked to APRT deficiency and may also help clarify testing for relatives.
When should I consider getting a genetic test?
Consider testing for APRT if you or your child have repeated kidney stones, crystals in the urine, or unexplained kidney damage, especially if stones began young or run in the family. Testing can also help when a stone has a rare makeup linked to APRT or after kidney problems continue without a clear cause.
A genetic result is only one part of your health story
Genetic findings can provide useful insight, but how much they explain varies by the condition and the specific type of variant. Over time, the way the body works is also shaped by many factors, including 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 viewed together with other parts of care. In other situations, a genetic result can give 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 genes can change how the body breaks down a drug, moves it through the body, or responds to it at its target, so the same treatment may work better for one person than for another. This is a common reason why some people get more benefit, fewer side effects, or more sensitivity from the same medication.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic variation affects a person’s response to medications. It focuses on links between genes and drugs to help explain why the same treatment may work differently in different people. For many medicines, genes influence both how the body handles a drug and how strong its effects may be. This information can support more informed, individualized treatment decisions. More on this topic is available in the LearnHub.
Drugs influenced by the APRT gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication choices. For questions about medicines, side effects, or any health changes, it is best to speak with your doctor.
History
APRT entered the medical literature through reports of people who formed unusual kidney stones made of 2,8-dihydroxyadenine, a finding that pointed to a specific inherited problem in purine metabolism. Initially understood only through visible traits, later recognized as tied to a specific gene, this condition helped connect a rare stone disease with a missing enzyme activity. In the 1970s and 1980s, researchers clarified the biochemical cause and showed that the condition could be passed through families. Building on this early work, scientists identified the APRT gene and described disease-causing variants in affected families from several countries. Over time, descriptions became more precise, and APRT deficiency is now recognized as an uncommon but treatable inherited cause of kidney stones and kidney injury.