Albinism :: essays research papers

Albinism ALBINISM Albinism. The word albinism refers to a group of inherited conditions. People with albinism have little or no pigment in their eyes, skin, or hair. Recently a test has been developed to identify carriers of the gene for ty-neg albinism and for other types in which the tyrosianase enzyme does not function. The test uses a sample of blood to identify the gene for the tryrosinase enzymes by its code in DNA. The above test does not apply to to one type of albinism, called X-linked ocular albinism. For X-linked inheritance, the gene for albinism is located on an X chromosome. Females have two X chromosomes, while males only have one X and one Y chromosome. This X-linked albinism accurs exclusively in males. The gene is passed from mothers who carry it to their sons. The mothers have subtle eye changes which an ophthalmogist could identigy, but mothers usually have normal vision. For each son born to a mother who carries the gene, there is one in two chance of having X-linked ocul ar albinism. The description is a hereditary deficiency pigmentation. This could involve the entire body or part of the body. This is believed to be caused by an enzyme deficiency involving the metabolism of melanin during prenatal development. This can be inherited by an dominant or recessive trait. In complete albinism, there is lack of pigmentation in skin and hair, as well as in retinal and iris tissue; in incomplete albinism, skin and hair may vary from pale to normal; in ocular albinism, function may vary from norma to impaired. Impairments may involve the retina and iris. If a person has albinism then they usually have somewhere between 20/70 and 20/200 visual. Ty-Neg albinism or also called type 1A results from a genetic defect in an enzyme called tyrosinase. Tyrosinase helps the body to change the amino acid tyrosine into pigment. An amino acid is a building block of protien. Albinism is passed from parent to their kid through genes. For nearly all types of albinism both pa rent must carry an albinism gene to have a child with albinism. Parents may have normal pigmentation but still carry the gene. When both parents carry the gene, there is a one in four chance at each pregnancy that the baby will be born with albinism. This type of inheritance is called autosomal recessive inheritance.