Did you know DNA influences your likelihood of age spots?
Genes involved in skin colour linked to higher incidence of age spots
“Mommy, how old is this Oak tree?” That’s a simple question with a sophisticated, yet easy answer. You explain the idea of tree rings to your child, how each year a tree adds a new layer of cells to form growth rings that can be counted to determine the age of a tree.
Comparatively, “how old is that person?” is a much more difficult question to answer. Of course there are visible signs of aging, like age spots. But unlike tree rings, guessing a person’s age based on the number of age spots is not an exact science. The appearance of age spots is influenced by different external factors, like ultraviolet (UV) light, and also strongly influenced by certain genetic variants.
Age spots, liver spots and solar lentigines, all refer to the blemishes that appear on our skin as we age. These brown, red, or sometimes nearly black spots are quite common in the areas of our body that are often exposed to the sun like the face, arms and legs. The development of age spots is attributed to the overproduction and accumulation of two pigments found in our skin, melanin and lipofuscin. Melanin is the pigment that gives colour to our skin, hair and eyes. Lipofuscin is often considered to be an age pigment as its levels increase with age.
According to one theory, age spots form when skin cells can no longer properly dispose of lipofuscin. This affects the function of neighbouring skin cells causing them to age. As these cells die, they release extra lipofuscin, generating darker spots on your skin. Alternatively, age spots mark sites of extra melanocytes, cells responsible for producing melanin. They are presumed to generate excessive amounts of melanin due to sun damage. This explains why age spots are found in areas of the skin that are more likely to be exposed to the sun.
Your likelihood of developing age spots is not dependent on just sun exposure, as your genes also come into play, particularly variants of MC1R, IRF4 and RALY. The MC1R gene encodes for the melanocortin 1 receptor, which helps regulate the production of melanin. There are multiple genetic variants, or altered versions of this gene, including rs1805007, rs1805009 and rs1805006. Each of these variants reduce the levels of the melanocortin 1 receptor and increase the risk for developing severe age spots.
The IRF4 gene produces a protein that controls numerous genes in the melanocytes, including those genes involved in melanin synthesis. The rs12203592 version of IRF4 affects the levels of this protein, and skin pigmentation. The RALY gene doesn’t appear to have a direct connection to skin colour, but it is close to another gene which affects skin colour (ASIP). The rs6059655 variant in the RALY/ASIP region is another genetic change linked to the appearance of age spots.
For the most part, age spots are harmless. However, they can be a cosmetic nuisance, especially when they form on the face. Whether or not you decide to embrace your heritage and declare that age spots are a sign of maturity, just remember that it is still important to minimize exposing your skin to UV radiation as much as possible.