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MC1R gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

MC1R gene

The MC1R gene provides instructions for a receptor that regulates skin and hair pigmentation and influences the body's response to ultraviolet radiation.

Normal Function

The MC1R gene provides instructions for making a protein called the melanocortin 1 receptor. This receptor plays an important role in normal pigmentation. The receptor is primarily located on the surface of melanocytes, which are specialized cells that produce a pigment called melanin. Melanin is the substance that gives skin, hair, and eyes their color.

Melanocytes make two forms of melanin: eumelanin and pheomelanin. The relative amounts of these two pigments help determine the color of a person's hair and skin. People who produce mostly eumelanin tend to have brown or black hair and dark skin that tans easily. Eumelanin also protects skin from damage caused by ultraviolet (UV) radiation in sunlight. People who produce mostly pheomelanin tend to have red or blond hair, freckles, and light-colored skin that tans poorly. Because pheomelanin does not protect skin from UV radiation, people with more pheomelanin have an increased risk of skin damage caused by sun exposure.

The melanocortin 1 receptor controls which type of melanin is produced by melanocytes. When the receptor is activated, it triggers a series of chemical reactions inside melanocytes that stimulate these cells to make eumelanin. If the receptor is not activated or is blocked, melanocytes make pheomelanin instead of eumelanin.

Health Conditions Related to Genetic Changes

Melanoma

Certain variations in the MC1R gene increase the risk of developing melanoma, a type of skin cancer that begins in melanocytes. These variations reduce the ability of the melanocortin 1 receptor to stimulate eumelanin production in melanocytes, resulting in fair skin. Because eumelanin normally protects skin from the harmful effects of UV radiation, a lack of this pigment leaves skin more vulnerable to damage from sun exposure. Skin damage caused by UV radiation from the sun is a major risk factor for developing melanoma.

Studies suggest that other variations in the MC1R gene may also increase the risk of developing melanoma in the absence of UV radiation-related skin damage. In these cases, melanomas can occur in people of dark or light skin coloring.

Oculocutaneous albinism

Certain genetic changes in the MC1R gene modify the appearance of people with oculocutaneous albinism type 2. This form of albinism, which is caused by mutations in the OCA2 gene, is characterized by fair hair, light-colored eyes, creamy white skin, and vision problems. People with genetic changes in both the OCA2 and MC1R genes have many of the usual features of oculocutaneous albinism type 2; however, they typically have red hair instead of the usual yellow, blond, or light brown hair seen with this condition.

Other Names for This Gene

  • MC1-R
  • melanocortin 1 receptor (alpha melanocyte stimulating hormone receptor)
  • Melanocortin-1 receptor
  • melanocyte stimulating hormone receptor
  • melanotropin receptor
  • MSH-R
  • MSHR_HUMAN

Genomic Location

The MC1R gene is found on chromosome 16.

Frequently Asked Questions

Having red hair or freckles is a strong clinical clue that you may carry one or more MC1R variants, but it is not definitive. About 80% of people with red hair have MC1R changes, yet some individuals without red hair also carry variants. Genetic testing is the only way to confirm your MC1R status.
Common loss‑of‑function MC1R variants roughly double the lifetime risk of melanoma, and certain “high‑risk” alleles can raise risk three‑ to four‑fold. The increase is additive to other factors such as UV exposure, family history, and number of nevi. Regular skin exams and diligent sun protection become especially important.
Testing is optional and most useful when it will change management. If you have a strong personal or family history of melanoma, atypical moles, or a phenotype (red hair, fair skin, many freckles) that suggests higher risk, a clinician may order MC1R testing to refine risk counseling. The result does not replace routine skin checks; it merely adds information for personalized prevention.
No specific sunscreen formulation is required, but individuals with MC1R variants should use broad‑spectrum (UVA + UVB) protection of at least SPF 30, reapply every two hours, and consider additional physical barriers (wide‑brimmed hats, clothing). Because pheomelanin offers less UV protection, diligent daily use is more critical than for people with higher eumelanin levels.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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