The METTL23 gene helps control how other genes are switched on, especially during brain development, and if it does not work properly, it can lead to developmental delay and intellectual disability. The protein made by this gene helps your cells manage gene activity by adding small chemical tags to certain proteins. Some people with disease causing variants in the METTL23 gene may also have delayed speech, learning difficulties, or subtle differences in growth or appearance.
What is a gene?
A gene is a stretch of DNA that holds instructions your cells use to make molecules or manage processes throughout the body. Some genes provide the directions for building proteins, which are the active parts of cells. Others mainly regulate when certain processes happen, where they take place, and how strongly they are carried out. Taken together, genes affect how the body grows and works, and they can influence how you respond to food, stress, or medicines. For a deeper look at this topic, more information is available in the LearnHub.
Overview
METTL23Gene function
What if the gene works
The METTL23 gene helps control how other genes are switched on inside cells. This supports normal brain development and routine cell activity.
Risk
What if the gene does not work
Variants in the METTL23 gene are linked to developmental delay and intellectual disability, often affecting speech and learning. Effects can range from milder to more marked, and more disruptive variants may lead to earlier or broader developmental features.
Treatment
What does that mean for your treatment
For pathogenic or loss-of-function variants in the METTL23 gene, no gene-specific treatment or medication approach is currently established. Treatment is based on the person's symptoms and support needs rather than a drug aimed at the METTL23 gene.
Conditions associated with METTL23
Gene function
What if the gene works
Cells use the METTL23 gene to fine tune which genes are active at different times. It makes a protein that adds a small methyl tag to certain proteins involved in gene control. Understanding how the METTL23 gene works in cells helps show how everyday gene activity stays organized.
The METTL23 gene makes an enzyme that places a small methyl tag on selected proteins. This can fine tune how those proteins carry out their jobs inside the cell nucleus.
By modifying proteins that help switch genes on, METTL23 supports transcription (the step where cells read genes into working instructions). This helps cells use the right genes at the right time.
What is a variant?
A genetic variant is a small change in the DNA sequence within a gene. These changes are common and help shape 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. In some cases, 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
Variants in the METTL23 gene can alter the protein’s shape or stability, which may weaken its activity or its ability to work with other cell proteins. More disruptive changes, such as an early stop signal, often mean little or no protein is made, while some missense variants leave partial function. These METTL23 gene variant effects can range from mild loss of activity to near complete loss of function.
How variants are linked to conditions
Pathogenic variants in both copies of the METTL23 gene are a rare but well-established cause of inherited developmental delay and intellectual disability. METTL23 gene variants linked to developmental delay often also affect speech and learning, and the severity can vary from one person to another.
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 directly affect health and simply reflect natural human variation. 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 play a role. In some situations, however, a single well-characterized variant in a particular 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 risks related to the METTL23 gene. For many living with METTL23 changes, the main risk depends on the specific genetic change itself and family inheritance, so personal guidance from a doctor or genetic counselor can be helpful.
Inheritance of METTL23 variants
METTL23-related conditions are inherited in an autosomal recessive pattern. This means a person usually develops the condition only when they inherit two disease-causing METTL23 variants, one from each parent. Parents who each carry one METTL23 variant are typically unaffected carriers, and with each pregnancy there is a 25% chance the child will inherit both variants, a 50% chance the child will be a carrier, and a 25% chance the child will inherit neither variant. In families asking how METTL23 variants are inherited, this pattern means boys and girls are affected equally.
What does my METTL23 result mean for my family?
For families with a disease-causing METTL23 result linked to intellectual disability, the pattern is recessive. This usually means parents may be healthy carriers, and brothers and sisters could also be carriers or, less often, have the same condition. Close relatives may want to learn whether the variant runs in the family, especially when planning children.
Genetic information
Genetic testing
How you find out about variants
METTL23 variants are usually found with genetic testing for METTL23 variants, using a blood or saliva sample. Labs may analyze the METTL23 gene in a multigene panel, exome sequencing, or genome sequencing. Results can show a benign variant, an uncertain finding, or a pathogenic variant that may help confirm a diagnosis.
When should I consider getting a genetic test?
Testing for changes in the METTL23 gene may be considered when a child has unexplained developmental delay or intellectual disability, especially if similar learning problems run in the family. A genetic result can sometimes help explain the cause and clarify whether both parents may be carriers.
A genetic result is only one part of your health story
A genetic finding can provide valuable insight, but how much it reveals depends on the condition and the type of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, influence how the body functions. For some conditions, especially those affected by many genes, genetic information offers context rather than certainty and is best interpreted alongside other parts of care. In other situations, a genetic result may give a clear answer. In areas such as medication response, genetic results can 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, moves, or responds to a drug, so the same treatment may work better for one person than for another. These inherited differences are common and can influence both how well a medicine helps and how sensitive someone may be to side effects.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in a person’s genes affect the way they respond to medicines. It studies links between genes and medications to clarify why the same treatment can work differently in different people. For many drugs, genes influence how strongly a medicine works or how the body handles it. This information can support more informed, personalized treatment decisions. More detail on this topic is available in the LearnHub.
Drugs influenced by the METTL23 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication choice or treatment response. Questions about side effects, new symptoms, or how medicines may affect overall health are best discussed with your doctor or pharmacist.
History
The METTL23 gene entered the medical literature through studies of families in which several relatives had the same inherited pattern of developmental differences, including intellectual disability. Early reports in the 2010s linked rare, disease causing variants in the METTL23 gene to autosomal recessive forms of this condition. From these first observations, research expanded steadily. Additional family studies from different populations helped confirm the association and showed that the clinical picture can vary from person to person. Over time, genetic sequencing made it easier to recognize METTL23 related conditions and to separate them from other inherited causes of developmental delay.