MC1R gene: Introduction
MC1R or melanocortin-1 receptor gene plays an important role in the normal pigmentation process in the body.
The gene encodes the receptor for the Melanocyte Stimulating Hormone (MSH), which is one of the two hormones that regulate pigmentation.
The MC1R receptor is also known as the melanocyte-stimulating hormone receptor or the melanotropin receptor.
Polymorphisms in the MC1R gene reduce the ability of the MC1R receptor to stimulate eumelanin production. This leads to melanocytes making more pheomelanin.
The MC1R receptor is active in cells other than melanocytes as well. These include cells involved in the body’s immune and anti-inflammatory responses.
Several SNPs are associated with this MC1R gene. They are primarily linked to fair skin, red or light hair and freckles.
They also show a varying risk of melanoma and non-melanoma skin cancers.
The SNPs of the MC1R gene also influence responses to opioid analgesics that are used to treat pain.
Research shows that opioids are more effective in females with red hair, and light skin and have lesser MC1R protein activity.
What are freckles?
Small, brown spots often present in the sun-exposed areas of the skin are called freckles.
They are almost always harmless and appear due to the overproduction of melanin in response to UV stimulation.
Freckles are essentially of two types: Ephelides and solar lentigines.
Ephelides are freckles that occur as a result of sun exposure.
Anyone who is exposed to sun rays or UV rays can develop these spots on their face, back of their hands and on their upper body.
This type of freckles is common in people with light skin and is generally seen in individuals with Caucasian and Asian descent.
The second type of freckles is called solar lentigines. It is a patch of dark skin that is harmless in nature and tend to appear in older Caucasians (above the age of 40yrs).
What causes freckles?
Freckles, as we now know, occur as a result of melanin that builds up under the skin, forming the spots.
There are two primary causes that have been cited for the development of freckles:
- Sun exposure: When the skin is exposed to the sun rays, the skin cells produce melanin, as a protective mechanism to protect the skin from sun damage.
So, we see freckles developing after a brief exposure to the sun.
Freckles tend to become darker on increased sun exposure and can also disappear when skin cells are replaced.
- Genetics: The second most common cause of freckles is the genetic susceptibility of an individual.
The human body produces two types of melanin – eumelanin (that protects the skin from sun’s UV rays) and pheomelanin (no protective function).
But, the type of melanin an individual produces depends on the MC1R gene.
How can one identify freckles from other skin pigmentations?
Our skin shows different types of pigmentations – moles, freckles, birthmarks, age spots, and sunspots.
But, how can we differentiate freckles from other similar looking marks?
Freckles, on exposure to the sun, appear as flat pigmented spots in clusters over a larger area of the skin.
They are irregular in shape but have clearly defined edges.
They are brown, tan or red in color and not more than 1-2 mm in size.
Who are at a risk for developing freckles?
Individuals with lighter or fair skin are at an increased risk of developing freckles and therefore, must take extra precautions before stepping out in the sun.
These individuals are also at a higher risk of developing skin cancer.
Freckles: What’s the genetic link?
| rsid | Risk allele | Implications |
|---|---|---|
| rs1540771 | t | 1.26X risk of freckles |
| rs1042602 | c | 1.23X risk of freckles |
| rs1805008 | t | 2.06X risk of freckles |
There are some SNPs on the MC1R gene that are associated with freckles, fair skin, and UV rays:
- rs1540771
The T allele of SNP rs1540771 is said to be associated with 1.26x risk of freckles, and UV sensitivity and brown hair.
- rs1042602
The rs1042602 SNP on the TYR gene is polymorphic in Europeans and the A allele derived from it is associated with light/fair skin, eye color and the absence of freckles.
- rs1805008
rs1805008 is also known as Arg160Trp or R160W and is one of the many SNPs that is found in the MC1R gene and is associated with red hair color, especially in the Irish population.
The T allele increases the risk of melanoma in this population with individuals having CT being carriers of red hair and a higher risk of melanoma compared to those having CC alleles.
Individuals with TT alleles have 7-10 times more chance of having red hair and at a greater risk of developing melanoma.
How to get rid of freckles?
Despite the genetic contribution to freckles, no one is actually born with it.
Freckles appear when an individual is exposed to the sun.
They tend to become darker during the summer months and fade away during the winter.
However, there are a few treatments and home remedies that one can use to get rid of these freckles.
- Use of sunscreen: Sunscreen protects your skin from the harmful effects of the sun and its UV rays.
Those who are prone to freckles must apply sunscreen every time they step out.
Using a sunscreen of SPF 30 or above can help the formation of new freckles but cannot help you get rid of the existing ones.
- Laser treatment: One can opt for laser treatment to get rid of the existing freckles.
There are different types of lasers that target specific areas in the skin.
It can take about 2-3 weeks to recover from the treatment and more than one session is needed for achieving the desired results.
- Retinoid cream: Retinoid cream consists of vitamin A which can help lighten the freckles.
The retinoids in the cream help absorb UV B radiation and prevent the formation of new lesions.
- Cryosurgery: This surgical technique uses extreme cold to destroy abnormal skin cells.
This method can be used to treat or get rid of freckles but it can have some side effects such as hypopigmentation or blistering, but it rarely causes scarring.
- Fading Cream: Fading creams are available as OTC products that contain hydroquinone.
The hydroquinone present in these creams suppresses the production of melanin and helps lighten the darkened areas of the skin.
- Using a chemical peel exfoliates the damaged areas of your skin.
When the damaged skin heals after a chemical peel, new skin appears without the freckles.
There are many natural or homemade remedies to lighten or get rid of freckles.
- Application of lemon juice on the required areas thrice a week can lighten the spots.
- Home-made scrubs using milk, honey, and oats is another effective method to reduce freckles.
- Milk products like buttermilk, yogurt or sour cream have skin lightening properties.
- Onions can also be used as exfoliants to lighten the freckles.
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Vitamin supplements
- Vitamin C: It is antioxidant in nature and has a protective effect against UV A and UV B rays.
Topical application of vitamin C is believed to reduce or lighten skin spots.
- Vitamin E: Topical application of vitamin E oil is very useful in reducing or lightening skin spots.
It also helps the skin heal from sun damage.
What are sunspots?
Sunspots, also called liver spots, are flat pigmented lesions that appear on the skin on exposure to the sun.
They are harmless in nature and are non-cancerous.
They appear in different shades of brown. Individuals who are over the age of 40 years are more prone to it.
Sunspots are commonly seen on the face, back of the hands, shoulders, and back.
What are the causes of sunspots?
Sunspots occur due to:
- Overexposure to sunrays/UV rays that results in overproduction of melanin in the skin.
- Sun allergy.
- Severe sunburns.
Can you get rid of sunspots?
Yes. Sunspots can be lightened or even removed completely using various home remedies and cosmetic procedures.
The cosmetic procedures need to be performed by a trained professional only and include procedures such as cryotherapy, microabrasion, chemical peels, laser treatment, or use of intense pulse light.
Home-remedies for sunspots
- Tea: Applying black tea water or green tea water to the sunspots twice a day for a month can help lighten them.
The antioxidants and active compounds in the tea are believed to bring about this effect.
- Apple cider vinegar: It has many health benefits and one of them is lightening the skin.
The acetic acid present in vinegar is believed to help lighten skin pigmentations.
- Milk: Applying sour milk, buttermilk, or yogurt also has a depigmentation effect on the affected area.
Lactic acid present in these substances is believed to bring about the required change.
Sunspot: What’s the genetic link?
| rsid | Risk Allele | Implications |
|---|---|---|
| rs885479 | a | 1.5X risk of sunspots |
| rs2228479 | a | 2X risk of sunspots |
- rs885479
Individuals with the rs885479 SNP of the MC1R gene having A allele had an increased risk for developing sunspots.
- rs2228479
This is an SNP of the MC1R gene and is also called as Val92Met or V92M.
It is associated with light and deep red hair and skin that is prone to sunburn.
The presence of the A allele increases the risk of an individual to developing sunspots.
You might also be interested in: A Guide To Analyze Your Genetic Variants For Psoriasis
What is tanning?
Tanning is a phenomenon wherein your skin darkens on exposure to the UV rays of the sun.
When exposed to the sun, your body produces melanin as a protective mechanism to absorb the harmful UV rays and protect the skin cells.
This excess melanin production leads to darkening of the skin.
Excessive absorption of UV radiation can cause sunburns.
It is quite common to see people getting a tan for the recreational purpose either by sunbathing (lying in the sun) or by using a tanning lamp found in indoor tanning beds.
One can also get a tan by using chemicals, an activity is known as sunless tanning.
What causes tanning?
When we walk out into the sun without sunscreen or have some parts of our body exposed, we are putting our skin cells at great risk of sun damage.
We often notice that when a dark-skinned individual is exposed to the sun, they tend to get darker, whereas light-skinned individuals turn red.
These changes in body color are due to the melanocytes producing melanin, resulting in tanning or sunburn.
Production of melanin in response to sun exposure is a protective function of the melanocytes.
Melanin absorbs the harmful UV radiations and protects the other skin cells.
So, the next time you sunbathe to get a tan or inadvertently get one while walking in the sun without sunscreen or adequately cover your body, you know why your body is getting tanned.
A tan may be a fashion statement, but just like sunburn, it is a form of skin damage and can put one at risk of developing cancer in the future.
Tanning and risk of melanoma
Melanoma is the term given to cancer that develops from skin cells called melanocytes.
It is also known as malignant melanoma and is a leading cause of death globally.
There has been a rise in melanoma cases primarily due to increased exposure to sun while sunbathing and indoor tanning devices.
The increase melanocyte in response to the UV rays is a grave risk factor for melanoma.
Home remedies to get rid of suntan
There are many useful home remedies we can try to get rid of tan or at least lighten the color.
- Exfoliation: It is the most commonly used method wherein a scrub is prepared using natural ingredients and rubbed on the skin to exfoliate or remove the topmost layers of the skin that form the dark color.
- Turmeric: Though it forms an integral part of the home-made scrub, turmeric application by itself on the tanned surface is also equally useful to fade a tan.
- Substances that lighten the skin: There are some commonly used substances and products that are known to lighten skin color and can be safely used at home to reduce your tan.
These include vitamin C, vitamin E, glycolic acid, retinoids, etc.
- Aloe vera: It is one of the most sought after substances for skin health.
It contains antioxidants that help lighten the skin and also heal and soothe the damaged skin.
Care should be taken to avoid any harsh chemical lighteners, peels, bleaches, etc., on tanned or sunburnt skin as they can aggravate the damage already done to the skin.
You might also want to read: Get flawless skin in 7 days
Tanning: What’s the genetic link?
| rsid | Risk allele | Implications |
|---|---|---|
| rs1805009 | c | Associated with poor tanning |
| rs2228479 | a | Associated with poor tanning |
- rs1805009
rs1805009 is an SNP that is known as Asp294His and is located on the MC1R gene. It is a variant that is linked with red hair and a low tendency to tan.
| Risk Allele | Risk |
|---|---|
| G/G | No risk of melanoma |
| C/G | 2.5X risk of developing melanoma |
| C/C | 3X risk of developing melanoma |
- rs2228479
rs2228479 is an SNP that is present on the MC1R gene and is associated with skin pigmentation. The A/A allele increases the individual’s susceptibility to melanoma whereas the G/G allele shows a lower risk.
References:
https://www.snpedia.com/index.php/MC1R
https://ghr.nlm.nih.gov/gene/MC1R#synonyms
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3977302/
https://www.snpedia.com/index.php/Rs2228479
