The SHBG gene makes a protein in the blood that carries sex hormones like testosterone and estrogen and helps control how much of these hormones can act on tissues. If this gene does not work as expected, hormone levels may become less balanced, which can affect puberty, menstrual patterns, fertility, hair growth, and some metabolic features. What this gene does can influence how your body uses hormones from day to day. Some gene changes are linked to higher or lower SHBG levels, while others do not seem to affect health in a clear way.
What is a gene?
Genes are stretches of DNA that hold instructions your cells use to make molecules or manage activities throughout the body. Some genes provide the directions for producing proteins, which are the active parts of cells. Others mainly regulate when certain processes happen, where they happen, and how strongly they run. Taken together, genes affect how the body develops and functions, and they can also shape how you respond to food, stress, and medications. For a deeper look at this topic, you can read more in the LearnHub.
Overview
SHBGGene function
What if the gene works
The SHBG gene helps make a blood protein that binds sex hormones such as testosterone and estrogen. This protein carries these hormones through the bloodstream and helps control how much is available to body tissues.
Risk
What if the gene does not work
Variants in the SHBG gene can lower sex hormone binding globulin levels, leaving more sex hormones unbound. Milder variants may have little effect, while more severe variants can be linked to menstrual irregularities, acne, extra hair growth, or fertility problems.
Treatment
What does that mean for your treatment
No SHBG-specific treatment or management approach is currently established for pathogenic or loss-of-function variants in the SHBG gene. In practice, care is guided by hormone levels, symptoms, and the underlying condition rather than the variant itself. The SHBG gene is mainly being studied as a biomarker that may help interpret sex hormone activity and metabolic risk.
Gene function
What if the gene works
Your liver makes a protein from the SHBG gene that travels in your blood. It attaches to sex hormones, especially testosterone and estradiol, and helps manage how they move around the body. Understanding how the SHBG gene affects hormone levels starts with this transport role.
The SHBG gene gives your body instructions to make a blood protein that carries testosterone, estradiol, and similar hormones. This helps these hormones travel through the bloodstream to different tissues.
By holding onto part of these hormones in the blood, this protein controls how much is free for tissues to use at a given time. That helps keep hormone signals more even from moment to moment.
When hormones are attached to this protein, they are less exposed to rapid breakdown and removal while circulating. This supports a more stable hormone supply for the body to draw on as needed.
What is a variant?
A genetic variant means a slight difference in a gene’s DNA sequence. These differences are common and are part of normal human variation, including differences in appearance, metabolism, or the way the body responds to environmental factors. Many variants do not have any noticeable effect and only represent natural genetic diversity. At times, though, a variant can change how a gene works enough to contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the SHBG gene can change how much sex hormone binding globulin is made, how well the protein folds, and how strongly it binds hormones in the bloodstream. Many are mild and mainly shift SHBG levels a little, while more disruptive variants may reduce protein stability, interfere with release from liver cells, or weaken hormone binding. This range helps explain how variants in the SHBG gene affect hormone binding, with effects that can be subtle in some people and more marked in others.
How variants are linked to conditions
Variants in the SHBG gene do not yet have a broadly confirmed link to a specific health condition, although research on how SHBG gene variants are linked to health conditions is still evolving. If you have a confirmed variant in this gene, your doctor or genetic counselor can explain what it may mean in the context of your own health and family history.
A variant is not necessarily a diagnosis
Genetic variants are a routine part of human biology and are widely found across the population. Most do not directly affect health and simply contribute to normal human variation. For many genes, having a variant associated with a condition points to a possible link, not a certain diagnosis, particularly when several genes and environmental influences play a role. In other situations, though, one well-defined variant in a particular gene is enough to establish a diagnosis.
Are there things that can increase or change my risk?
Changes in the SHBG gene seem to affect risk mainly by shifting SHBG levels, but overall risk also depends a lot on body weight, insulin resistance, hormone levels, age, and some medicines. These factors can change the chance of problems linked with low or high SHBG, such as type 2 diabetes or hormone-related symptoms.
Inheritance of SHBG variants
There is not yet a broadly confirmed disease specific SHBG gene inheritance pattern used in routine clinical genetics, although research continues to clarify how inherited SHBG gene variants may influence hormone binding and blood levels. For people looking into SHBG gene inheritance, it helps to know that the SHBG gene is located on chromosome 17, which is an autosome. That means you inherit one copy of the SHBG gene from your mother and one copy from your father.
What does my SHBG result mean for my family?
There is not yet a broadly confirmed inherited pattern tied to a specific, well-established health condition for the SHBG gene. If you have a specific SHBG result and want to understand what it could mean for close relatives, a doctor or genetic counselor can help interpret it in the context of your family and health history.
Genetic information
Genetic testing
How you find out about variants
SHBG genetic testing looks for changes in the SHBG gene using a blood or saliva sample. A lab reads your DNA code and compares it with the usual sequence to identify variants that may help explain hormone test results or family findings. Results show whether a variant was found, but they do not by themselves diagnose a hormone condition.
When should I consider getting a genetic test?
There is not yet a broadly established reason to test the SHBG gene in routine care. Testing decisions are usually based on your symptoms, hormone levels, and family history, together with a doctor or genetic counselor.
A genetic result is only one part of your health story
A genetic finding can provide useful information, but how much it reveals varies based on the condition and the type of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, affect how the body functions. For some conditions, especially those influenced by many genes, genetic information offers context rather than certainty and is best understood as part of the broader picture of care. In other situations, a genetic result may give a clear answer. In areas such as medication response, genetic results can also help make sense of individual experiences.
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 bloodstream, or responds to it at its target. This is common and helps explain why the same treatment works well for one person, has little effect in another, or causes more side effects in someone else. In practice, genetics is one part of the picture, along with age, other health conditions, and other medicines.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can affect the way people respond to medications. It focuses on links between genes and drugs to help explain why the same treatment may work differently from one person to another. For many medicines, genes influence both how the body handles a drug and how strong its effects are. This information can support treatment decisions that are more informed and more tailored to the individual. More detail on this topic is available in the LearnHub.
Drugs influenced by the SHBG gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding how medicines are chosen or used, so general concerns about symptoms, hormones, or side effects are best discussed with your doctor. SHBG has been studied in research on hormone-related treatments because it affects how much sex hormone is free in the blood, but this is not currently used as a standard guide for prescribing.
History
Researchers first recognized the protein linked to the SHBG gene in the 1950s while studying how sex hormones travel in blood, and it was originally called testosterone-estradiol-binding globulin. Initially understood only through blood protein studies, later recognized as tied to a specific gene, it became an important part of endocrine research. In the following decades, scientists purified the protein, refined its name to sex hormone-binding globulin, and mapped the SHBG gene in the human genome. Building on this early work, scientists uncovered more about the SHBG gene when cloning methods in the late 20th century made it possible to study its structure and inherited differences more directly. These steps helped connect older hormone research with modern genetic testing and population studies.