The HSD17B12 gene helps your cells make certain fats and process some hormones, which supports healthy cell membranes, brain development, and vision. If this gene does not work properly, the body may have trouble building these fats, and some people develop a rare inherited condition with developmental delay, seizures, movement problems, or eye findings such as vision changes. Genetic results in HSD17B12 are usually interpreted in the context of symptoms, because the effects can vary from person to person.
What is a gene?
A gene is a stretch of DNA that carries instructions your cells use to make molecules or regulate activities in the body. Some genes contain the code for proteins, the parts of cells that do the work. Other genes mainly control when certain processes happen, where they take place, and how strongly they run. Together, genes affect how the body develops and functions, and they can shape how you respond to food, stress, or medications. To explore this topic in more detail, you can learn more in the LearnHub.
Overview
HSD17B12Gene function
What if the gene works
The HSD17B12 gene helps cells make long chain fats used in cell membranes and energy storage. It also helps process certain hormones, including estrogen.
Risk
What if the gene does not work
More disruptive variants in the HSD17B12 gene can cause a rare neurodevelopmental condition with developmental delay, epilepsy, and movement problems. Milder variants may leave some function intact, which can influence when symptoms begin and how pronounced they are.
Treatment
What does that mean for your treatment
No treatment or management approach specific to the HSD17B12 gene is currently established. The HSD17B12 gene is being studied as a possible drug target and biomarker in some cancers, but this has not led to routine gene-directed treatment.
Gene function
What if the gene works
The HSD17B12 gene supports a basic job your cells do every day: managing certain fats. It helps with the steps that turn some fatty acids into longer forms. Those longer fats are useful for cell membranes and other routine cell work. This helps explain what the HSD17B12 gene does in the body from day to day.
This gene helps cells lengthen certain fatty acids by adding small carbon pieces. That step supplies very long-chain fats your body uses every day.
The longer fats made through HSD17B12 are used to build parts of cell membranes. These membranes help cells keep their shape, organize inside spaces, and carry out routine tasks in an orderly way.
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 the way the body responds to environmental influences. Many variants do not have any noticeable effect and simply represent natural genetic variation. Sometimes, though, a variant can change how a gene works more significantly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the HSD17B12 gene can weaken the enzyme in different ways, from mildly lowering its activity to nearly stopping it. Some changes alter the protein's shape or stability, while more disruptive variants can shorten it or prevent enough from being made, disrupting the cell's ability to make long chain fats. This range helps explain how HSD17B12 gene variants affect protein function, and people with two more severe variants often have earlier symptoms and wider body involvement.
How variants are linked to conditions
Changes in both copies of the HSD17B12 gene can cause a rare inherited condition linked to developmental delay, seizures, and vision problems. In published cases, HSD17B12 gene variants are linked to conditions that may also include hearing loss, movement difficulties, and slower growth. When clearly disease causing variants are found in both gene copies, they can confirm the diagnosis.
A variant is not necessarily a diagnosis
Variants in genes are a usual part of being human and are widely found across the general population. Most do not directly affect health and instead reflect normal human diversity. For many genes, having a variant linked to a condition points to a possible association, not a definite diagnosis, especially when several genes and environmental factors are involved. In some situations, though, one well-characterized variant in a particular gene can be 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 the HSD17B12 gene. Anyone concerned about their personal or family risk can talk with a doctor or genetic counselor for advice based on their own history.
Inheritance of HSD17B12 variants
For families looking into how HSD17B12 variants are inherited, the well-established pattern is autosomal recessive. This means a person usually develops an HSD17B12-related condition only when they inherit one disease-causing variant from each parent. Parents who each carry one variant are often unaffected themselves, 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 either variant.
What does my HSD17B12 result mean for my family?
For families with an HSD17B12-related condition, the result is usually relevant in a recessive pattern. This often means parents are healthy carriers, and brothers or sisters may also be carriers or, less often, may have the condition. Other relatives on both sides of the family may also carry the same gene change.
Genetic information
Genetic testing
How you find out about variants
To look for changes in the HSD17B12 gene, genetic testing usually uses a blood sample or cheek swab and reads the gene's DNA sequence. This is how you find out about HSD17B12 variants: a lab checks for changes that may help confirm a diagnosis or clarify carrier status. Results are interpreted alongside your symptoms and family history.
When should I consider getting a genetic test?
Genetic testing for the HSD17B12 gene may be worth considering if a child has unexplained developmental delay, seizures, movement problems, or vision loss, especially when more than one family member is affected. It can also make sense if a blood relative is known to carry a harmful HSD17B12 change or has this rare inherited condition.
A genetic result is only one part of your health story
Genetic results can provide meaningful insight, although how much they reveal depends on the condition and the kind of variant involved. Over time, how the body works is also shaped by many other factors, including lifestyle, environment, age, and medical history. In some conditions, especially those influenced by many genes, genetic information provides context rather than certainty and is best understood together with 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 genes can change how the body absorbs, breaks down, or uses a drug. Because of this, the same medication may work well for one person, have less effect in another, or cause more side effects in someone who is more sensitive to it. These differences are common and are one part of why treatment response varies from person to person.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can shape a person’s response to medications. It studies connections between genes and drugs to better explain why the same treatment may work differently from one person to another. For many medicines, genes affect both how strongly a drug works and how the body processes it. This information can help support more informed, more individualized treatment decisions. More about this topic is available in the LearnHub.
Drugs influenced by the HSD17B12 gene
When should I seek medical advice?
There is no broadly confirmed evidence that changes in this gene should guide medication choices at this time. If you have questions about a medicine, side effects, or changes in your health, speak with your doctor.
History
In recent decades, awareness of the HSD17B12 gene’s role has grown within research rather than public life. It was identified in the early 2000s as scientists were sorting the many genes in the 17β hydroxysteroid dehydrogenase family, a group involved in processing hormones and fats. Early studies first linked it to estrogen related pathways, and later work broadened that picture. From these first observations, research expanded steadily. Investigators then connected the HSD17B12 gene to key cell processes and, over time, to rare inherited conditions when both gene copies carry a harmful variant. Its history is mainly a story of laboratory discovery, with understanding becoming more precise as genetic sequencing improved.