The MRAP gene helps the adrenal glands respond to ACTH, a signal from the brain that tells them to make cortisol, a hormone needed for blood sugar, blood pressure, and the body’s stress response. If the MRAP gene does not work properly, the body may make too little cortisol, leading to an inherited form of adrenal insufficiency called familial glucocorticoid deficiency. People with disease-causing variants may develop low blood sugar, vomiting, poor weight gain, dehydration, or darker skin, often starting in infancy or childhood.
What is a gene?
A gene is a piece of DNA that carries instructions your cells use to make molecules or regulate activities in the body. Some genes provide the directions for producing proteins, which are the functional parts of cells. Others mainly guide 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 influence how you respond to food, stress, or medications. For a more detailed explanation, you can read more in the LearnHub.
Overview
MRAPGene function
What if the gene works
The MRAP gene helps adrenal glands respond to ACTH, a signal from the pituitary gland. This allows the body to make cortisol, a hormone that supports blood sugar, blood pressure, and the stress response.
Risk
What if the gene does not work
Variants in the MRAP gene can cause glucocorticoid deficiency, where the body responds poorly to ACTH and cortisol stays low. People may develop darkened skin, low blood sugar, or poor growth, with milder or severe variants affecting timing and severity.
Treatment
What does that mean for your treatment
For a pathogenic variant in the MRAP gene, no MRAP-specific treatment or drug selection approach is currently established. Management follows standard adrenal insufficiency care rather than a treatment chosen specifically because of the MRAP gene.
Conditions associated with MRAP
Gene function
What if the gene works
In the adrenal glands, the MRAP gene helps cells respond to ACTH, a hormone that tells them when to make cortisol. You can think of it as a helper that gets the ACTH receptor into the right place and keeps the signal working smoothly. Understanding how the MRAP gene helps the adrenal glands respond to ACTH makes its day to day role easier to picture.
MRAP helps the ACTH receptor, the cell's receiver for this hormone, reach the surface of adrenal cells. This lets the hormone message arrive at the right spot and be recognized.
After ACTH attaches, MRAP helps the receptor pass that message into the cell. This close partnership is central to what the MRAP gene does in the adrenal glands.
By supporting this hormone signal, MRAP helps adrenal cells start the steps that make cortisol. Cortisol supports everyday body functions, including energy balance, blood pressure, and the normal response to stress.
What is a variant?
A genetic variant is a minor change in the DNA sequence within a gene. These changes are common and help account for normal human diversity, such as differences in appearance, metabolism, or the way the body responds to environmental influences. Many variants do not lead to any noticeable effect and simply represent natural genetic variation. In some situations, 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 MRAP gene variants affect adrenal hormone signaling depends on how much they disrupt the MRAP protein. Some variants lower protein production or alter its shape, so it cannot properly help the ACTH receptor reach the cell surface or signal normally. Milder variants may leave some activity, while more severe variants can cause near-complete loss of function. In people with pathogenic variants, this often lines up with earlier onset and stronger features of familial glucocorticoid deficiency.
How variants are linked to conditions
The link between variants in the MRAP gene and primary adrenal insufficiency is well established: pathogenic variants in both copies cause familial glucocorticoid deficiency type 2, a rare inherited condition. This diagnosis involves isolated cortisol deficiency and often very high ACTH levels, while people with one altered copy usually remain healthy.
A variant is not necessarily a diagnosis
Variants in DNA are a usual feature of human biology and are widespread across the population. Most do not directly affect health and instead reflect normal human variation. For many genes, having a variant tied to a condition points to a possible link, not a certain diagnosis, particularly when more than one gene and environmental influences play a role. In some situations, though, one well understood variant in a particular gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For MRAP, risk is mainly shaped by family genetics rather than lifestyle. A child’s chance of having the related adrenal condition is higher when both parents carry a harmful change in the MRAP gene, and this can be more likely in families where blood relatives have children together. There is not enough evidence to say that diet, exercise, or other daily habits lower this genetic risk.
Inheritance of MRAP variants
MRAP-related conditions are inherited in an autosomal recessive pattern. In practical terms, MRAP gene inheritance usually means a child is affected only when they inherit one altered copy from each parent; parents who carry one altered copy are usually unaffected carriers. When both parents carry an MRAP gene variant, each pregnancy has a 25% chance of an affected child, a 50% chance of a carrier child, and a 25% chance of a child who inherits neither variant. Because the MRAP gene is on chromosome 21, sons and daughters are affected at similar rates.
What does my MRAP result mean for my family?
For MRAP, family implications are usually those of a recessive condition. Brothers and sisters may also have the condition or may be healthy carriers, and parents are often carriers without symptoms. More distant relatives can sometimes be carriers too, especially on the same side of the family.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a change in the MRAP gene, doctors use genetic testing for MRAP variants on a blood or saliva sample. A lab reads the gene’s DNA code and checks for variants. Results may show a harmful variant, a benign variant, or a variant of uncertain significance, meaning the lab cannot yet tell whether it affects health.
When should I consider getting a genetic test?
Genetic testing for the MRAP gene may be worth considering when a baby or child has signs of inherited low cortisol from the adrenal glands, especially repeated low blood sugar, seizures, unusual skin darkening, or poor growth. It can also help when close relatives have the same condition or an unexplained adrenal problem.
A genetic result is only one part of your health story
Genetic test findings can provide useful information, but how much they show depends on the condition and the kind of variant involved. Many other factors, including lifestyle, environment, age, and medical history, also influence how the body works over time. For some conditions, especially those shaped by many genes, genetic information provides context rather than certainty and is most useful when considered alongside other parts of care. In other situations, a genetic result can offer a clear answer. In areas such as medication response, these results can help put individual experiences into context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how your body responds to medicines. Small differences in genes can change how a drug is absorbed, broken down, or used by the body, so the same treatment may work better for one person than for another. This is common and can influence how much benefit someone feels from a medicine or how sensitive they are to side effects.
What is Pharmacogenetics?
Pharmacogenetics is the area of study that examines how genetic differences affect response to medication. It explores connections between genes and drugs to better explain why treatment can work differently from one person to another. For many medicines, genes help shape how strongly a drug works or how the body handles it. This information can support more informed, individualized treatment decisions. To learn more about this topic, you can visit the LearnHub.
Drugs influenced by the MRAP 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 questions about side effects, new symptoms, or medication changes are best discussed with your doctor.
History
The MRAP gene entered medical genetics in the mid 2000s through studies of families with familial glucocorticoid deficiency, a rare inherited condition affecting the body’s stress hormone system. In 2005, researchers identified disease causing variants in the MRAP gene and showed that this finding explained cases that had not been linked to earlier known genes. Once considered rare, now recognized as an important part of human genetics, MRAP helped clarify why some children had low cortisol despite a normal looking adrenal gland on routine evaluation. Building on this early work, scientists confirmed its role in a second form of familial glucocorticoid deficiency, often called type 2. These discoveries gave clinicians a clearer genetic diagnosis for affected families and marked an important step in understanding inherited adrenal conditions.