The AMT gene helps your cells break down glycine, a natural amino acid your body makes and uses. The protein made by this gene helps your cells keep glycine from building up to high levels, especially in the brain. If a person inherits nonworking copies of the AMT gene, glycine can rise too much and cause glycine encephalopathy, a rare condition that often begins in newborns with sleepiness, feeding problems, low muscle tone, seizures, and later developmental challenges.
What is a gene?
Genes are stretches of DNA that carry instructions your cells use to make molecules or manage activities in the body. Some genes provide the directions for producing proteins, which are the working parts of cells. Others mainly 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 explore this subject in more detail, you can learn more in the LearnHub.
Overview
AMTGene function
What if the gene works
The AMT gene helps your cells break down glycine, a building block of protein. This supports energy production and keeps glycine levels in a healthy range, especially in the brain and liver.
Risk
What if the gene does not work
Variants in the AMT gene can cause glycine encephalopathy, often beginning in infancy with low muscle tone, seizures, breathing problems, and developmental delay. Milder or more severe variants can change when symptoms begin and how strongly they affect a person.
Treatment
What does that mean for your treatment
Pathogenic variants in the AMT gene can support treatment with glycine-lowering therapy such as sodium benzoate, often alongside medicines that reduce NMDA receptor overactivity, commonly dextromethorphan. These treatments may help with seizures, alertness, feeding, and comfort, although response varies and they do not reverse existing brain injury.
Conditions associated with AMT
Gene function
What if the gene works
Your cells rely on the AMT gene to process glycine, a small amino acid from food and normal body activity. It works inside mitochondria, the parts of cells that help manage energy. This process helps keep everyday cell chemistry balanced and supports other pathways your body uses to make key building blocks.
The AMT gene helps your cells process glycine, a common amino acid from food and normal protein turnover. It does this inside mitochondria, the parts of cells that help manage energy.
AMT passes a small part of glycine to folate, a B vitamin related carrier molecule your cells use in many reactions. This helps supply material your cells can use to make important building blocks.
By linking glycine processing with folate use, the AMT gene supports steady day to day cell chemistry. This captures what the AMT gene does in your body during everyday metabolism.
What is a variant?
A genetic variant is a small difference in the DNA sequence within a gene. These changes are common and are part of normal human diversity, such as 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. Sometimes, though, a variant can change how a gene functions more significantly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
How AMT gene variants affect protein function depends on the change: some make the protein fold poorly, become unstable, or lose much of its activity in the cell pathway that breaks down glycine. Others weaken its contact with partner proteins or its lipoate group (a small attached chemical helper). Milder variants may leave some residual activity, while more severe variants can nearly abolish it. In glycine encephalopathy, this often shapes how early symptoms appear and how severe they are.
How variants are linked to conditions
Pathogenic variants in the AMT gene cause glycine encephalopathy, also called nonketotic hyperglycinemia. This AMT gene related condition often begins in newborns with low muscle tone, feeding problems, seizures, and developmental difficulties, though some people have a milder or later onset form. When testing finds disease causing variants in both copies of the AMT gene, it can confirm the diagnosis.
A variant is not necessarily a diagnosis
Genetic variants are common across the general population and are a normal feature of human biology. Most do not directly affect health and instead reflect natural differences among people. For many genes, having a variant associated with a condition points to a possible link, not a confirmed diagnosis, particularly when several genes and environmental influences play a role. Still, in some situations, one well-characterized variant in a particular gene is enough to confirm the diagnosis.
Are there things that can increase or change my risk?
For AMT-related disease, risk is mainly set by the gene changes a child inherits, usually one from each parent. There is not broad evidence that diet, exercise, or other everyday exposures change the chance of having the condition. In someone already living with it, illness or poor feeding can make symptoms harder to manage.
Inheritance of AMT variants
Variants in the AMT gene linked to AMT related glycine encephalopathy are inherited in an autosomal recessive pattern. This means a child usually inherits one altered copy from each parent, and parents who each carry one variant are typically unaffected carriers. With each pregnancy, two carrier parents 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. In practical terms, how variants of the AMT gene are inherited depends on both parents passing on the altered copy.
What does my AMT result mean for my family?
For families with an AMT-related condition, close relatives may also carry the same gene change even if they feel completely well. Brothers and sisters may be affected or may be healthy carriers, and future children in the family could also be at risk if both parents carry an AMT change. Because of this, family members sometimes choose to learn whether they are carriers or whether the result is present in other relatives.
Genetic information
Genetic testing
How you find out about variants
To look for changes in the AMT gene, doctors use AMT gene testing on a blood sample, saliva sample, or cheek swab. The lab reads the gene’s DNA code and checks for variants that may help confirm a diagnosis, clarify carrier status, or explain a family history.
When should I consider getting a genetic test?
Genetic testing for the AMT gene may be considered if a baby or child has signs of a rare condition where glycine, a natural body chemical, builds up, causing severe sleepiness, poor feeding, seizures, or low muscle tone. It can also help when this condition is known in the family.
A genetic result is only one part of your health story
A genetic result can provide useful insight, but how much it reveals depends on the condition and the kind of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, affect how the body functions. For some conditions, especially those shaped by many genes, genetic information offers context rather than certainty and is most helpful when considered 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 a person’s DNA 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 medication may work well for one person, work less well for another, or cause more side effects in someone who is more sensitive to it.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in genes can affect a person’s response to medications. By looking at connections between genes and drugs, it helps explain why the same treatment may work differently from one person to another. For many medicines, genes play a part in how the body processes a drug and how strong its effects may be. This information can support treatment decisions that are more informed and more individualized. You can read more about this topic in the LearnHub.
Drugs influenced by the AMT gene
When should I seek medical advice?
There is no broadly confirmed role for this gene in guiding how medicines are chosen or used right now. Questions about side effects, new symptoms, or how any treatment fits with your overall health are best discussed with your doctor or pharmacist.
History
Families and communities once noticed patterns that seemed to pass from parent to child, but the AMT gene entered medicine through studies of a rare inherited condition rather than public attention. In the 1960s, doctors began describing infants with very high glycine levels and a distinctive neurologic picture later known as nonketotic hyperglycinemia. From these first observations, research expanded steadily, and by the 1990s scientists had linked some cases to variants in the AMT gene. This work helped show that the condition could result from changes in different genes within the same biological pathway. Over time, descriptions became more precise as genetic testing made it possible to confirm AMT related cases and separate them from similar conditions.