Albinism Essay Research Paper AlbinismIn the past

Albinism Essay, Research Paper Albinism In the past, albinos were usually treated with fear or awe. They were sometimes killed at birth. Albino births were common enough in some groups not to cause any excitement. For example, among the San Blas Indians of Panama, one in approximately 130 births is an albino. In the mid-nineteenth century, albinos were exhibited in sideshows. Whole families were displayed at times and were described as a unique race of might people. They were said to live underground and to come out only at night when the light was dim and would not hurt their eyes. Albinism is a genetic defect if the integumentary system. Albinism occurs when the body fails to produce melanin. Melanin forms in a special cell called the melanocyte. This cell is found in the

skin, in the hair follicle, and in the iris and retina of the eye. There are many steps in converting the amino acid tyrosine to melanin pigment. Two types of melanin form: black-brown eumelanin and red-blood pheomelanin. Trosiase is the major enzyme involved in the formation of melanin pigment. Tyrosinase is responsible for converting tyrosine to DOPA and on to dopaguinone. The dopaguinone then forms black-brown eumelanin or red-yellow pheomelanin. The tyrosinase enzyme is made by the tyrosinase gene on chromosome 11, and alterations of this gene can produce on type of albinism because the tyrosinase enzyme made by the altered gene does not work correctly. Two additional enzymes called tyrosinasa-related protein 1 or DHICA oxidase and tyrosinase-related protein 2 or dopachrome

tautomerase are important in the formation of eumelanin pigment. The gene for DHICA oxidase in on chromosome 9 and the gene for dopachrome tautomerase in on chromosome 9. Alterations of the DHICA oxidase gene are associated with a loss of function of this enzyme and this causes one type of albinism. An alteration of the gene for dopachrome tautomerase does not produce albinism. Three other genes make proteins that are also involved in melanin pigment formation and albinism, but the exact role of these proteins remains unknown. These genes are the P gene on chromosome 15, the Hermansky–Pudlak syndrome gene on chromosome 10, and the ocular albinism gene on the X chromosome. The gene carrying the defect that produces albinism is recessive, which means that both parents must carry

this recessive gene in order to produce a child with the condition. When both parents carry the gene (and neither has albinism), there is a one in four chance with each pregnancy that their child will have albinism. The inheritance pattern of ocular albinism is alittle different. This condition is X-linked, meaning that the recessive gene for ocular albinism is located on the X chromosome. X-linked ocular albinism appears just about only in males who inherit the condition from their mothers. Albinism is a recessive inherited defect in melanin metabolism in which pigment is absent from the hair, skin, and eyes (oculocutaneous albinism) or just from the eyes (ocular Albinism). Albinos tend to be children of parents who were first cousins. For a long time, the term “albinism”

referred only to people who had white hair, white skin, and blue eyes. Individuals who had OCA and pigmented hair and eyes were identified, particularly in the African and African-American population, and terms such as ‘incomplete albinism’, ‘partial albinism’ of ‘imperfect albinism’ were used for this, but these terms are inappropriate and are no longer used. In the 1960’s, Dr. Carl Witkop invented the hairbulb incubation test to separate pigmenting and non-pigmenting types of OCA and stared to use the terms “ty-neg” or “tyrosinase-negative” and “ty-pos” or “tyrosinase-positive” OCA. Freshly plucked hairbulbs from a person with OCA were place in a solution of tyrosine or dopa in a test tube and watched to see if pigment formed in the cells in the