Albinism is an inherited genetic disorder. Both parents must carry the albinism gene to have a child with albinism. The albinism gene is a recessive gene, meaning that a child has to receive a copy from both parents to have the disorder. If the child gets a copy of the gene from just one parent, he or she will not have symptoms of albinism. If both parents carry the gene, there is a one-in-four chance with each pregnancy that the baby will be born with albinism.
One type of albinism, called X-linked ocular albinism, is inherited from the mother. In this case, the gene for albinism is located on an X chromosome. Females have two X chromosomes, while males have one X chromosome and one Y chromosome. X-linked ocular albinism appears almost exclusively in males. The gene for it is passed from mothers (who carry it without developing the condition) to their sons. The mothers generally have normal vision. For each son born to a mother who carries the gene, there is a one-in-two chance of having X-linked ocular albinism.
Albinism occurs in about one in 17,000 births.
Image reprinted, with permission, from Wygnanski-Jaffe T, Focal Points, Introductory Genetics for the Ophthalmologist, American Academy of Ophthalmology, 2005.
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