Linear chains of amino acids that singly or in multiples of two or more form into proteins. Chains of just two amino acids are called, chains of three are, and any more are polypeptides.inear chains of amino acids that singly or in multiples of two or more form into proteins. Chains of just two amino acids are called, chains of three are, and any more are polypeptides.
Vitiligo: A Common Cause of Loss of Skin Pigment. Melanin is the pigment that gives the skin its characteristic color. Vitiligo is caused by a loss of pigment in the skin, due to destruction of pigment-forming cells known as melanocytes. Although vitiligo affects all races equally, it is more noticeable in dark-skinned people. Vitiligo can cause cosmetic problems.
Vitiligo is a long-term problem in which growing patches of skin lose their color. It can affect people of any age, gender, or ethnic group. The patches appear when melanocytes within the skin die off. Melanocytes are the cells responsible for producing the skin pigment, melanin, which gives skin its color and protects it from the sun's UV rays.