Freckles

# What are freckles? Freckles are small brown to reddish pigment spots that occur mainly in fair-skinned people and can be intensified by sunlight. They are caused by an increased accumulation of melanin, the pigment responsible for the color of our skin and hair. The development of freckles is a complex process in which both genetic and environmental factors are involved. Genetic predisposition plays a major role in the predisposition to the formation of freckles. Certain genetic variants can influence the production and distribution of melanin in the skin, which can lead to a higher likelihood of freckles appearing. In addition to genetic factors, sun exposure also has an influence on the formation of freckles. People with fair skin who are exposed to the sun more often tend to develop more freckles as their skin is more sensitive to UV radiation and produces more melanin to protect it. Overall, freckles are the result of a combination of genetic predisposition and environmental factors. > ## Good to know > > In the summer months, when sun exposure is higher, freckles tend to become darker and more numerous. In winter, when there is less sunlight, they often fade and their number may decrease. These seasonal changes are due to the fact that freckles are stimulated by UV radiation. # Genetics meets sunlight In addition to genetic factors, sun exposure also influences the formation of freckles. Fair-skinned people who are more exposed to the sun tend to develop more freckles as their skin is more sensitive to UV radiation and produces more melanin to protect it. Overall, freckles are the result of a combination of genetic predisposition and environmental factors. Freckles are harmless and do not pose a health risk, but can indicate an increased UV sensitivity of the skin. They are particularly common in people with red or blonde hair and fair skin. # What does genetics have to do with it? Some gene variants are particularly strongly associated with the formation of freckles. These genes and their specific SNPs play an important role in the pigmentation of the skin and the tendency to develop freckles. The SNP rs35563099 is located near the genes LINC02674 and RAB11FIP2. These genes are involved in cellular communication processes and the regulation of pigmentation. The C/T polymorphism at this site can affect the expression of these genes and thus the pigmentation of the skin. Variants of the SNP rs35563099 can alter the probability of freckle formation. The T variant of this SNP is often associated with an increased tendency to lighter skin and more freckles. This is because the T allele may affect the expression of pigment regulators in the affected genes, leading to altered distribution and production of melanin. The LINC02674 and RAB11FIP2 genes also play a role in cell structure and the regulation of signaling pathways that can also influence skin pigmentation. The SNP rs35563099 probably influences these regulatory processes, which may be reflected in skin pigmentation and the tendency to form freckles. The MC1R gene is crucial for the regulation of melanin production. Variants in this gene, such as the SNP rs35063026, are associated with an increased likelihood of freckles and red hair. These variants often lead to reduced production of eumelanin (dark pigment) and increased production of pheomelanin (reddish pigment), which favors the formation of freckles. The ASIP gene controls skin pigmentation through its antagonistic effect on the MC1R gene. The SNP rs6059655 in the ASIP gene is associated with an increased tendency to lighter skin and more freckles. This variant can influence melanin distribution and thus increase the likelihood of freckles occurring. The BNC2 gene is an important factor in skin pigmentation, and genetic variants in this gene can influence the tendency to form freckles. In particular, the SNP rs62543565 within the BNC2 gene has been associated with the frequency and intensity of freckles. This SNP alters the regulation of pigmentation processes by influencing the expression of genes responsible for melanin production. The A variant of this SNP is often found in people with an increased tendency to freckles, as it favors an altered melanin distribution in the skin. The TERT gene has an indirect influence on pigmentation and therefore on the formation of freckles. It codes for telomerase, an enzyme that stabilizes the telomeres at the ends of the chromosomes. Variants in the TERT gene that affect telomerase activity can influence skin ageing and pigmentation in general. Although the direct link between TERT and freckles is less pronounced, altered telomerase activity can increase the skin's sensitivity to UV radiation and thus promote the formation of pigmentation spots such as freckles.