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It is caused by melanocyte or melanin depletion, or a decrease in the amino acid tyrosine, which is used by melanocytes to make melanin. [2] Some common genetic causes include mutations in the tyrosinase gene or OCA2 gene. [3] [4] As melanin pigments tend to be in the skin, eye, and hair, these are the commonly affected areas in those with ...
This is an accepted version of this page This is the latest accepted revision, reviewed on 22 January 2025. "Skin pigmentation" redirects here. For animal skin pigmentation, see Biological pigment. Extended Coloured family from South Africa showing some spectrum of human skin coloration Human skin color ranges from the darkest brown to the lightest hues. Differences in skin color among ...
Melanosomes, which are organelles containing melanin, must be transported and increased during hyperpigmentation and tanning, while they shrink during hypopigmentation. [4] Skin pigmentation is frequently caused by sun exposure. To protect itself against UV radiation from the sun, the body makes more melanin. As a result, the skin may become ...
As we age, the follicles produce less melanin, so when a new hair grows, it looks gray or white, TODAY.com previously reported. This usually starts in the mid-30s, Friedman notes. This usually ...
Several skin whitening agents, including tyrosinase inhibitors, have been found to cause an increase in the expression of tyrosinase, which by itself would increase melanin synthesis. [ 43 ] Microphthalmia-associated transcription factor (MITF) is the master transcription factor that controls the expression of TYR, TRP1, and TRP2, MART1 ...
Furthermore, these people have been living in the far north for less than 7,000 years. As their founding populations lacked alleles for light skin colour, they may have had insufficient time for significantly lower melanin production to have been selected for by nature after being introduced by random mutations. [65] "This was one of the last ...
Melanin is brown, non-refractile, and finely granular with individual granules having a diameter of less than 800 nanometers. This differentiates melanin from common blood breakdown pigments, which are larger, chunky, and refractile, and range in color from green to yellow or red-brown. In heavily pigmented lesions, dense aggregates of melanin ...
Melanin is the primary determinant of the degree of skin pigmentation and protects the body from harmful ultraviolet radiation. The same ultraviolet radiation is essential for the synthesis of vitamin D in skin, so lighter colored skin – less melanin – is an adaptation related to the prehistoric movement of humans away from equatorial ...