The BCHE gene helps your body break down certain medicines, especially the short acting muscle relaxant succinylcholine used during anesthesia. If this gene does not work well, those drugs can last much longer than expected, causing prolonged muscle weakness and a need for breathing support until the medicine wears off. Some people first learn about the BCHE gene after an unexpected reaction during surgery or a family history of this drug sensitivity.
What is a gene?
Genes are sections of DNA that carry instructions your cells use to make molecules or regulate activities in the body. Some genes provide the code for proteins, which are the parts of cells that do much of the work. Others are mainly involved in controlling when certain processes happen, where they take place, and how active they are. Taken together, genes affect how the body grows and works, and they can influence how you respond to food, stress, or medicines. To go further into this subject, you can find more in the LearnHub.
Overview
BCHEGene function
What if the gene works
The BCHE gene helps make an enzyme in the blood that breaks down certain chemicals, including some medicines used during anesthesia. This supports normal drug handling in the body.
Risk
What if the gene does not work
Variants in the BCHE gene can lower butyrylcholinesterase activity, usually causing little day to day effect but often prolonging paralysis after succinylcholine or mivacurium. Milder and more severe variants can change how strong and long lasting this effect is.
Treatment
What does that mean for your treatment
Pathogenic variants in the BCHE gene can make succinylcholine and mivacurium last much longer during anesthesia, so these drugs are usually avoided. Anesthesiologists generally use other muscle relaxants instead. If exposure occurs, treatment is supportive, with breathing assistance until the drug effect wears off.
Conditions associated with BCHE
Gene function
What if the gene works
The BCHE gene helps your body clear certain chemical messengers, medicines, and other compounds from the bloodstream. Its protein is made mainly in the liver and works largely in blood. When it is working as expected, these substances are broken down in a controlled way so they do not linger longer than needed.
The BCHE gene makes an enzyme that breaks down choline ester compounds in the blood. This cleanup role helps clear certain natural and man made chemicals after they have done their job.
Its enzyme helps break down several medicines, including some short acting muscle relaxants used during surgery. This is part of how the BCHE gene helps break down certain medicines in the body.
Its protein also acts as a circulating scavenger, meaning it can bind and help neutralize some ester chemicals in the blood. This supports chemical balance before those compounds spread more widely through the body.
What is a variant?
A genetic variant is a small difference in the DNA sequence of a gene. These differences are common and help explain normal human diversity, such as variation in appearance, metabolism, or how the body responds to environmental influences. Many variants do not cause any noticeable effect and simply represent natural genetic variation. In some cases, though, a variant can change how a gene works more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the BCHE gene can make the enzyme unstable, reduce how much is made, or change the part that binds certain anesthetic drugs. Milder changes may leave some activity, while more severe variants can cause little or no enzyme activity. These differences help explain why BCHE gene variants are linked to succinylcholine sensitivity: some people have only a brief delay in drug breakdown, while others can have much longer paralysis after exposure.
How variants are linked to conditions
Certain variants in the BCHE gene cause butyrylcholinesterase deficiency, a condition often recognized through BCHE-related anesthesia sensitivity. People with this diagnosis may have unusually prolonged muscle relaxation, weakness, or a slower return of breathing after medicines such as succinylcholine or mivacurium. Other BCHE findings have been studied in common health conditions, but those links are not established in the same clear way.
A variant is not necessarily a diagnosis
Variants in genes are a routine part of human biology and are common throughout the general population. Most do not directly affect health and simply reflect natural human diversity. For many genes, carrying a variant associated with a condition suggests a possible link rather than a confirmed diagnosis, especially when multiple genes and environmental factors play a role. In some situations, though, a single well-characterized variant in a specific gene can be enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For BCHE, inherited gene changes are the main factor that affect risk, especially the chance of having unusually long muscle relaxation or slow waking after certain anesthesia drugs such as succinylcholine. Risk can become more noticeable with exposure to these medicines, and low BCHE activity from liver disease, pregnancy, or some medications can add to the effect.
Inheritance of BCHE variants
Variants in the BCHE gene are inherited in an autosomal recessive pattern. This means a person usually inherits one changed copy from each parent, and parents who each carry one BCHE gene variant are often unaffected themselves. When both parents are carriers, each child has a 25% chance of inheriting both variants and having BCHE-related enzyme deficiency, a 50% chance of being a carrier, and a 25% chance of inheriting neither variant. In practical terms, how BCHE gene variants are inherited means the condition can appear in brothers or sisters even when there is no family history in earlier generations.
What does my BCHE result mean for my family?
A BCHE result can matter for close relatives because this condition usually runs in families in a recessive pattern. Brothers, sisters, and children may also carry a changed BCHE copy, and some relatives may have the condition if they inherited two changed copies. This can be especially relevant before surgery, since certain muscle relaxant medicines can last much longer than expected in people with BCHE-related enzyme deficiency.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for BCHE variants uses a saliva or blood sample to read the BCHE gene. It can show whether you carry a variant linked to slower breakdown of certain medicines, especially the anesthetic drugs succinylcholine and mivacurium. Results usually report the specific variant found, or note that no tested variant was detected.
When should I consider getting a genetic test?
Consider BCHE genetic testing if you or a close relative had unusually long weakness or needed help breathing for longer than expected after anesthesia, especially during surgery. It can also help explain a blood test showing very low activity of this enzyme and support safer planning for future procedures.
A genetic result is only one part of your health story
A genetic result can provide useful insight, but what it tells you depends on the condition and the kind of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, influence how the body works. For some conditions, especially those shaped by many genes, genetic information offers context rather than certainty and is best understood 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 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. This helps explain why the same treatment works well for one person, works less well for another, or causes more side effects in someone else.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can shape the way a person responds to medications. By looking at links between genes and drugs, it helps explain why the same treatment may work differently from one person to another. For many medicines, genes affect both how the body processes a drug and how strong its effects are. This information can support more informed, more individualized treatment decisions. You can read more about this topic in the LearnHub.
Drugs influenced by the BCHE gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in routine medication decisions, so general concerns about medicines are best discussed with your doctor. BCHE has been linked in research to unusually long effects from some medicines used during anesthesia, especially certain muscle relaxants. Seek medical advice before surgery if you or a close relative had trouble breathing or could not move for longer than expected after anesthesia.
History
The history of the BCHE gene is closely tied to anesthesia and one of the earliest clear examples of inherited differences in drug response. In the 1950s, doctors noticed that a small number of patients stayed paralyzed much longer than expected after receiving succinylcholine during surgery. Researchers later linked this pattern to inherited changes in blood cholinesterase activity, and laboratory testing such as the dibucaine number helped make the connection clearer. Once considered rare, now recognized as an important part of human genetics, this finding became a landmark in pharmacogenetics, the study of how genes influence medicine response. From these first observations, research expanded steadily. Over time, the BCHE gene became a classic teaching example of why family history can matter in anesthetic care.