MRAP

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What is the official name of the MRAP gene?

The official name of this gene is “melanocortin 2 receptor accessory protein.”

MRAP is the gene's official symbol. The MRAP gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the MRAP gene?

The MRAP gene provides instructions for making a protein called melanocortin-2 receptor accessory protein (MRAP). This protein transports another protein, called the melanocortin-2 receptor (or more commonly the adrenocorticotropic hormone [ACTH] receptor), from the interior of the cell to the cell surface. Specifically, the MRAP protein transports the ACTH receptor from a cell structure called the endoplasmic reticulum (ER), which is involved in protein processing and transport, to the cell membrane so that the receptor can function. The MRAP protein is also needed to turn on (activate) the ACTH receptor.

At the cell membrane, the activated ACTH receptor attaches (binds) to ACTH, which triggers the production of a group of hormones called glucocorticoids. These hormones, which include cortisol and corticosterone, aid in immune system function, play a role in maintaining normal blood sugar levels, help trigger nerve cell signaling in the brain, and serve many other purposes in the body.

How are changes in the MRAP gene related to health conditions?

familial glucocorticoid deficiency - caused by mutations in the MRAP gene: At least 13 mutations in the MRAP gene have been found to cause familial glucocorticoid deficiency. This condition is characterized by potentially life-threatening low blood sugar (hypoglycemia), recurrent infections, and skin coloring darker than that of other family members (hyperpigmentation). MRAP gene mutations account for approximately 20 percent of cases of this condition. Most of these mutations lead to the production of a protein that cannot interact with the ACTH receptor and so is unable to transport it out of the ER to the cell membrane. As a result, the ACTH receptor is not at the cell surface where it is needed to bind to ACTH. Without the binding of the ACTH receptor to its hormone, there is no signal to trigger the adrenal glands to produce glucocorticoids. A shortage of these hormones impairs blood sugar regulation, immune system function, and other cellular functions, leading to the signs and symptoms of familial glucocorticoid deficiency.

Where is the MRAP gene located?

Cytogenetic Location: 21q22.1

Molecular Location on chromosome 21: base pairs 32,291,812 to 32,314,783

The MRAP gene is located on the long (q) arm of chromosome 21 at position 22.1.

More precisely, the MRAP gene is located from base pair 32,291,812 to base pair 32,314,783 on chromosome 21.

See How do geneticists indicate the location of a gene? in the Handbook.

Where can I find additional information about MRAP?

You and your healthcare professional may find the following resources about MRAP helpful.

Educational resources - Information pages
Endocrinology: An Integrated Approach (2001): Feedback Control of Glucocorticoids
Genetic Testing Registry - Repository of genetic test information (1 link)

You may also be interested in these resources, which are designed for genetics professionals and researchers.

PubMed - Recent literature
OMIM - Genetic disorder catalog
Research Resources - Tools for researchers (3 links)

What other names do people use for the MRAP gene or gene products?

B27
C21orf61
FALP
fat cell-specific low molecular weight protein
fat tissue-specific low MW protein
GCCD2
melanocortin-2 receptor accessory protein
MRAP_HUMAN

See How are genetic conditions and genes named? in the Handbook.

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding MRAP?

adrenal glands ; axis ; cell ; cell membrane ; deficiency ; endoplasmic reticulum ; ER ; familial ;gene ; glucocorticoid ; glucocorticoids ; hormone ; hypoglycemia ; immune system ; nerve cell ;protein ; receptor ; tissue

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

References (7 links)

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook