The MDH2 gene helps your cells make energy inside mitochondria, the parts of cells that act like power plants. If it does not work properly, the body may struggle to meet energy needs, which can affect the brain, muscles, growth, and development. Rare harmful variants in the MDH2 gene can cause an inherited metabolic condition, and some variants are linked to a higher chance of paraganglioma or pheochromocytoma (uncommon tumors in nerve and adrenal tissue).
What is a gene?
Genes are sections of DNA that carry instructions cells use to make molecules or guide activities in the body. Some genes provide the directions for building proteins, which do much of the cell’s work. Others are mainly involved in regulating when certain processes happen, where they happen, 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. For a more detailed look at this topic, you can read more in the LearnHub.
Overview
MDH2Gene function
What if the gene works
The MDH2 gene helps your mitochondria turn food into usable energy. It makes an enzyme used in the cell’s energy cycle. This supports steady energy production in many tissues.
Risk
What if the gene does not work
Milder to more severe variants in the MDH2 gene can cause a rare energy production condition with developmental delay, low muscle tone, seizures, and high lactate, often starting in infancy. Some variants are also linked to pheochromocytoma or paraganglioma.
Treatment
What does that mean for your treatment
For pathogenic variants in the MDH2 gene, no treatment or management approach tied specifically to this gene is currently established. The MDH2 gene is being studied as a cancer metabolism target and biomarker in early research, but this has not changed routine care.
Conditions associated with MDH2
Gene function
What if the gene works
Your cells use the MDH2 gene in their mitochondria, the parts of cells that make most of the body’s energy. It supports a central energy pathway that helps turn food into usable fuel. Understanding MDH2 gene function in mitochondria helps explain how cells keep up with steady day to day energy needs.
MDH2 helps convert malate into oxaloacetate inside mitochondria. This step keeps a major energy pathway moving so cells can release energy from food and support ATP, the cell’s main energy source.
As it works, MDH2 loads energy onto NAD+, forming NADH. Mitochondria use NADH as an important input when making cellular energy.
MDH2 is part of the malate aspartate shuttle, a system that moves energy from the cell fluid into mitochondria. This helps cells use fuel efficiently across 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 account for normal human diversity, including variation in appearance, metabolism, or how the body responds to environmental influences. Many have no noticeable effect and simply represent natural genetic variation. In some instances, though, a variant can more substantially change how a gene functions and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the MDH2 gene can change the enzyme’s shape, stability, or activity, which may lower how well cells handle key energy chemistry inside mitochondria. In many explanations of how MDH2 gene variants affect enzyme activity, milder changes leave some residual function, while more severe variants can sharply reduce or nearly eliminate activity. Some variants also make the protein less stable, so cells break it down sooner. This range in functional impact can influence how strongly mitochondrial pathways are disrupted.
How variants are linked to conditions
Pathogenic variants in the MDH2 gene can cause a rare inherited mitochondrial condition often called MDH2 deficiency. People who inherit two disease-causing variants may develop problems that start in infancy or childhood, including developmental delay, low muscle tone, seizures, and episodes of high lactate in the blood, sometimes with changes seen on brain scans. Reports on the MDH2 gene and related conditions mainly center on this childhood-onset mitochondrial disease.
A variant is not necessarily a diagnosis
Genetic variants are a routine part of human biology and are widespread in the general population. Most do not have a direct effect on health and simply reflect normal human variation. For many genes, carrying a variant associated with a condition suggests a possible link rather than a definite diagnosis, especially when several genes and environmental factors also contribute. In some situations, though, a single well-characterized variant in a specific gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
There isn't yet broadly confirmed evidence on specific factors that increase or reduce risk related to the MDH2 gene. If you have an MDH2 change, a doctor or genetic counselor can help explain what it may mean for your own health and family history.
Inheritance of MDH2 variants
MDH2-related conditions can follow different inheritance patterns depending on the specific condition and variant. Some changes in the MDH2 gene linked to pheochromocytoma or paraganglioma are inherited in an autosomal dominant way, which means a parent carrying the variant can pass it to each child with a 50% chance. Other MDH2-related conditions, including a rare metabolic condition, are inherited in an autosomal recessive way, so a child usually needs to inherit one altered copy from each parent. This means MDH2 inheritance is not the same in every family.
What does my MDH2 result mean for my family?
MDH2 results can mean different things for family members because this gene is linked to more than one inherited condition. Some MDH2 changes are tied to a dominantly inherited tumor risk, so close relatives may also carry the same change and may wish to discuss testing. Other MDH2 changes cause a recessive condition, which means relatives may be healthy carriers without symptoms. The family impact depends on the exact MDH2 change and the condition it is linked to.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the MDH2 gene, genetic testing for MDH2 variants uses a blood or saliva sample to read the gene’s DNA code. Results may identify a variant, show no significant change, or find a result that needs expert interpretation.
When should I consider getting a genetic test?
Consider MDH2 genetic testing when a child has signs of a rare problem with how cells make energy, such as early seizures, developmental delay, low muscle tone, or repeated high lactic acid levels. Testing also makes sense if a close relative has an MDH2 change or this condition.
A genetic result is only one part of your health story
Genetic findings can provide useful information, but how much they explain depends on the condition and the kind of variant involved. How the body works over time is also shaped by many factors, including lifestyle, environment, age, and medical history. For some conditions, especially those influenced 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 help place personal experiences in context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how your body responds to medicines. Some people break down a drug more slowly or more quickly, while others may be more or less sensitive to its effects. This helps explain why the same treatment works well for one person but not as well for another, or why side effects can differ. These differences are common and are one of several reasons medication response varies from person to person.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in genes can affect a person’s response to medications. It studies 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 strongly a drug works and how the body processes it. This information can support treatment decisions that are more informed and more personalized. To explore this subject in greater detail, you can learn more in the LearnHub.
Drugs influenced by the MDH2 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication choice or dose, so questions about side effects, new symptoms, or changes in how medicines affect you are best discussed with your doctor.
History
MDH2 entered medical research through classic studies of cell energy in the mid 20th century, when scientists mapped the chemical steps cells use to turn food into usable fuel. From these first observations, research expanded steadily as researchers separated the mitochondrial form of malate dehydrogenase from related enzymes elsewhere in the cell. This helped place the MDH2 gene within the growing picture of how mitochondria support everyday body functions. Later, advances in DNA sequencing connected inherited variants in the MDH2 gene with rare metabolic conditions and, in some families, certain neuroendocrine tumors. Over time, descriptions became more precise, turning MDH2 from a laboratory enzyme into a gene with clear clinical relevance.