Human skin color neural, or viral causes. The incidence worldwide is less than 1%. Individuals affected by vitiligo sometimes suffer psychological discomfort because of their appearance. Increased melanin production, also known as hyperpigmentation, can be a few different phenomena: Aside from sun exposure and hormones, hyperpigmentation can be caused by skin damage, such as remnants of blemishes, wounds or rashes. This is especially true for those with darker skin tones. The most typical cause of darkened areas of skin, brown spots or areas of discoloration is unprotected sun exposure. Once incorrectly referred to as liver spots, these pigment problems are not connected with
Pigment dispersing factor mRNA levels, while PDF knockouts show reduced protein. Similar behavioral and molecular phenotypes are observed in loss of PDF and VIP receptors. Pigment dispersing factor Pigment dispersing factor (pdf) is a gene that encodes the protein PDF, which is part of a large family of neuropeptides. Its hormonal product, pigment dispersing hormone (PDH), was named for the diurnal pigment movement effect it has in crustacean retinal cells upon its initial discovery in the central nervous system of arthropods. The movement and aggregation of pigments in retina cells and extra-retinal cells is hypothesized to be under a split hormonal control mechanism.