Your liver uses the HAO1 gene to make an enzyme that helps turn glycolate, a natural body chemical, into other substances. If this gene does not work, glycolate can build up in blood and urine. This rare condition, called glycolate oxidase deficiency, often causes few or no day to day symptoms. In medicine, this gene is important because lowering its activity can reduce oxalate, a substance that can contribute to some kidney stone conditions.
What is a gene?
Genes are stretches of DNA that give your cells instructions for making molecules or directing activities in the body. Some genes carry the code for proteins, which do much of the cell’s work. Other genes are used mainly to regulate when certain processes happen, where they happen, and how active they are. Taken together, genes affect how the body develops and works, and they can also influence how you respond to food, stress, or medications. To go further into this topic, you can find more in LearnHub.
Overview
HAO1Gene function
What if the gene works
The HAO1 gene helps liver cells break down glycolate, a natural substance from food and normal metabolism. Its protein works in peroxisomes, small cell compartments, to process glycolate so the body can handle it normally.
Risk
What if the gene does not work
Variants in the HAO1 gene can reduce or stop glycolate oxidase activity, so cells convert less glycolate into glyoxylate. Milder variants may leave some activity, while more severe variants can cause near complete loss of this step.
Treatment
What does that mean for your treatment
No treatment or management approach is currently established specifically for pathogenic variants in the HAO1 gene. The HAO1 gene is, however, a well established drug target: lumasiran lowers HAO1 activity to reduce oxalate production in primary hyperoxaluria type 1.
Gene function
What if the gene works
Your liver uses the HAO1 gene during everyday chemical processing. It helps handle glycolate, a small natural acid made as your body breaks down certain substances. Understanding what the HAO1 gene does makes it easier to see how liver cells keep related chemicals moving in a steady way.
The HAO1 gene helps liver cells change glycolate into glyoxylate, another small acid used in normal metabolism. This is a routine part of how the body processes certain natural compounds.
Its protein works inside peroxisomes, small spaces in cells that handle certain chemical reactions. Keeping this step in the right place helps liver cells process these compounds in an orderly way.
By moving glycolate into the next stage, the HAO1 gene supports steady flow through related metabolic pathways. This helps your body manage everyday byproducts from food and normal cell activity.
What is a variant?
A genetic variant is a small difference in the DNA sequence of a gene. These changes are common and are part of normal human diversity, including differences in appearance, metabolism, or the way 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 functions more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Many HAO1 gene variants change how the cell makes or handles the glycolate oxidase protein, and this explains how HAO1 gene variants affect enzyme activity. Milder variants may partly reduce the protein’s shape, stability, or work rate, while more severe variants, including some splice or early stop changes, can leave little or no working enzyme. This can lead to a larger buildup of glycolate inside cells and in body fluids, with a broader biochemical effect.
How variants are linked to conditions
Pathogenic variants in the HAO1 gene can cause isolated glycolic aciduria, a very rare inherited condition in which glycolate is high on urine testing, but many people have few or no symptoms. In reported families, this finding has not shown the kidney problems seen in primary hyperoxaluria, so the main effect is usually an abnormal lab result rather than a clear illness. This is the best established answer to how HAO1 gene variants are linked to conditions.
A variant is not necessarily a diagnosis
Genetic variants are a normal feature of human biology and are common throughout the general population. Most do not have a direct effect on health and instead represent natural human diversity. For many genes, carrying a variant associated with a condition indicates a possible link rather than a definite diagnosis, especially when several genes and environmental factors are involved. 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 is not yet broadly confirmed evidence on specific factors that increase or reduce health risk related to HAO1. Anyone concerned about personal or family risk can talk with a doctor or genetic counselor for advice based on their own medical history.
Inheritance of HAO1 variants
HAO1-related findings are inherited in an autosomal recessive pattern. This means a person usually needs to inherit two HAO1 gene variants, one from each parent, for the related metabolic finding to be present. Parents who each carry one variant are typically carriers, and with each pregnancy there is a 25% chance the child inherits both variants, a 50% chance the child is a carrier, and a 25% chance the child inherits neither variant. In practical terms, how HAO1 gene variants are inherited usually means boys and girls are affected equally, because the HAO1 gene is on chromosome 20, not a sex chromosome.
What does my HAO1 result mean for my family?
There is not yet a broadly confirmed inheritance pattern tied to a specific health condition for HAO1, and some changes in this gene have been found in people without clear symptoms. If you have a specific HAO1 result and questions about what it could mean for relatives, a doctor or genetic counselor can help explain it in the context of your family.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for HAO1 variants usually uses a blood or saliva sample. A lab reads the HAO1 gene to look for DNA changes, sometimes as part of a broader gene panel, exome, or genome test. Results may show a variant linked to a health condition, a common benign change, or a finding that needs more interpretation.
When should I consider getting a genetic test?
Genetic testing for the HAO1 gene may be considered if you or your child has repeated urine tests showing high levels of a body chemical called glycolate, especially during a workup for kidney stone or oxalate problems. It can also help when a close relative has a confirmed HAO1-related finding.
A genetic result is only one part of your health story
A genetic result can provide valuable insight, but how much it explains varies by the condition and the type of variant. Over time, many factors, including lifestyle, environment, age, and medical history, also shape how the body works. For some conditions, especially those influenced by many genes, genetic information offers context rather than certainty and is most useful when viewed alongside other parts of care. In other situations, a genetic result may give a clear answer. In areas like medication response, genetic results can also help make individual experiences easier to understand.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. This helps explain why the same treatment may work well for one person, cause more side effects in another, or seem less effective in someone else. Differences in how the body absorbs, breaks down, and responds to drugs are common, and genes are one part of that picture along with age, health, and other medicines.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in a person’s genes can affect the way they respond to medicines. It studies gene-drug relationships to help explain why the same treatment may work differently in different people. For many medicines, genes can influence both how strongly a drug works and how the body handles it. This information can support more informed, personalized treatment choices. More details on this topic are available in the LearnHub.
Drugs influenced by the HAO1 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in how people respond to medicines, so questions about treatment, side effects, or other health concerns are best discussed with your doctor. HAO1 is being studied mainly as a treatment target in rare oxalate conditions, rather than as a gene used to guide everyday prescribing.