Melanin (redirected from melanin deficiency)

melanin /mel·a·nin/ (mel´ah-nin) any of several closely related dark pigments of the skin, hair, choroid coat of the eye, substantia nigra, and various tumors, produced by polymerization of oxidation products of tyrosine and dihydroxyphenol compounds.

---

mel·a·nin (ml-nn)

n.

Any of a group of naturally occurring dark pigments composed of granules of highly irregular polymers that usually contain nitrogen or sulfur atoms, especially the pigment found in skin, hair, fur, and feathers.

---

Melanin

A dark insoluble pigment found in humans in the skin, hair, choroid layer of the eye, and a part of the brain called the substantia nigra.

Mentioned in: Albinism, Moles, Skin Pigmentation Disorders

---

melanin (meˑ·l·nin),

n a substance produced by melanocytes found in the deepest layer of the epidermis; protects the skin from the effects of the sun's harmful rays. Variations in skin color are a result of the level of melanin produced by each individual.

---

melanin (mel´nin),

n the dark amorphous pigment of melanotic tumors, skin, oral mucosa, hair, choroid coat of the eye, and substantia nigra of the brain.

---

melanin

a dark, sulfur-containing pigment normally found in the hair, skin, ciliary body, choroid of the eye, pigment layer of the retina, and certain nerve cells. It occurs abnormally in certain tumors, known as melanomas, and is sometimes excreted in the urine when such tumors are present (melanuria).

---

melanin deficiency

hypopigmentation, leukoderma, hypomelanosis.

excess melanin

hyperpigmentation, hypermelanosis, melanism, melanoderma, melanotrichia.

melanin-stimulating hormone

see melanocyte-stimulating hormone.