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. They have inherited altered genes that do not make the usual amounts of a pigment called melanin. One person in 17,000 in the U.S.A. has some type of albinism. Albinism affects people from all races. Most children with albinism are born to parents who have normal hair and eye color for their ethnic backgrounds. Sometimes people do not recognize that they have albinism. A common myth is that people with albinism have red eyes. In fact there are different types of albinism and the amount of pigment in the eyes varies. Although some individuals with albinism have reddish or violet eyes, most have blue eyes. Some have hazel or brown eyes. However, all forms of albinism are associated with vision problems.
Causes and symptoms
Albinism is an inherited problem caused by an alteration in one or more of the genes that are responsible for directing the eyes and skin to produce or distribute melanin, which is a photoprotective pigment that absorbs ultraviolet (UV) light coming from the sun so that the skin is not damaged. Sun exposure normally produces a tan, which is an increase in melanin pigment in the skin. Many people with albinism do not have melanin pigment in their skin, do not tan with exposure to the sun, and as a result develop sunburn . Over time, people with albinism may develop skin cancers if they do not adequately protect their skin from sun exposure.
Melanin is also important in the eyes and brain, but it is not known what role melanin plays in those areas. Parts of the retina do not develop correctly if melanin pigment is not present during development. Also nerve connections between the retina and brain are altered if melanin is not present in the retina during development.
Albinism is a autosomal recessive disease, which means that a person must have two copies of the defective gene to exhibit symptoms of the disease. The child therefore inherits one defective gene responsible for making melanin from each parents. Because the task of making melanin is complex, there are many different types of albinism, involving a number of different genes.
It is also possible to inherit one normal gene and one albinism gene. In this case, the one normal gene provides enough information to make some pigment, and the child has normal skin and eye color. The child has one gene for albinism. About one in 70 people are albinism carriers, with one defective gene but no symptoms; they have a 50 percent chance of passing the albinism gene to their child. However, if both parents are carriers with one defective gene each, they have a one in four chance of passing on both copies of the defective gene to the child, who will have albinism. There is also a type of ocular albinism that is carried on the X chromosome and occurs almost exclusively in males because they have only one X chromosome and, therefore, no other gene for the trait to override the defective one.
Genetics on Albanism
Oculocutaneous albinism is generally the result of the biological inheritance of genetically recessive alleles (genes) passed from both parents of an individual for example OCA1 and OCA2. Some rare forms are inherited from only one parent. There are other genetic mutations which are proven to be associated with albinism. All alterations, however, lead to changes in melanin production in the body.[6][11] Some of these are associated with increased risk of skin cancer ( see list of such genetic variations).
The chance of offspring with albinism resulting from the pairing of an organism with albinism and one without albinism is low. However, because organisms (including humans) can be carriers of genes for albinism without exhibiting any traits, albinistic offspring can be produced by two non-albinistic parents. Albinism usually occurs with equal frequency in both sexes.[6] An exception to this is ocular albinism, which it is passed on to offspring through X-linked inheritance. Thus, ocular albinism occurs more frequently in males as they have a single X and Y chromosome, unlike females, whose genetics are characterized by two X chromosomes.[12]
There are two different forms of albinism: a partial lack of the melanin is known as hypomelanism, or hypomelanosis and the total absence of melanin is known as amelanism or amelanosis.
Treatments for Albinism
To date, there's no way to supplement melanin in people with albinism or to force the body to make it. Skin can't be darkened, and eye anatomy can't be fully corrected. But hope is not lost. Treatments for albinism complications are readily available. Early visits to low-vision eye specialists can improve vision dramatically. Here's what they might prescribe
Work Cited
"What Is Albinism?" NOAH. N.p., 1995. Web. 4 May 2014. < http://www.albinism.org/publications/what_is_albinism.html>.
Sims, Judith L. "Albinism." Children Health. N.p., n.d. Web. 4 May 2014. < http://www.healthofchildren.com/A/Albinism.html>.
King, Richard A., et al. "Facts about Albinism." International Albinism Center, University of Minnesota. http://www.cbc.umn.edu/iac/facts.html>
Nasr, Susan L. "How Albinism Works." N.p., n.d. Web. 4 May 2014. < http://health.howstuffworks.com/skin-care/problems/medical/albinism4.htm>.
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. They have inherited altered genes that do not make the usual amounts of a pigment called melanin. One person in 17,000 in the U.S.A. has some type of albinism. Albinism affects people from all races. Most children with albinism are born to parents who have normal hair and eye color for their ethnic backgrounds. Sometimes people do not recognize that they have albinism. A common myth is that people with albinism have red eyes. In fact there are different types of albinism and the amount of pigment in the eyes varies. Although some individuals with albinism have reddish or violet eyes, most have blue eyes. Some have hazel or brown eyes. However, all forms of albinism are associated with vision problems.
Causes and symptoms
Albinism is an inherited problem caused by an alteration in one or more of the genes that are responsible for directing the eyes and skin to produce or distribute melanin, which is a photoprotective pigment that absorbs ultraviolet (UV) light coming from the sun so that the skin is not damaged. Sun exposure normally produces a tan, which is an increase in melanin pigment in the skin. Many people with albinism do not have melanin pigment in their skin, do not tan with exposure to the sun, and as a result develop sunburn . Over time, people with albinism may develop skin cancers if they do not adequately protect their skin from sun exposure.
Melanin is also important in the eyes and brain, but it is not known what role melanin plays in those areas. Parts of the retina do not develop correctly if melanin pigment is not present during development. Also nerve connections between the retina and brain are altered if melanin is not present in the retina during development.
Albinism is a autosomal recessive disease, which means that a person must have two copies of the defective gene to exhibit symptoms of the disease. The child therefore inherits one defective gene responsible for making melanin from each parents. Because the task of making melanin is complex, there are many different types of albinism, involving a number of different genes.
It is also possible to inherit one normal gene and one albinism gene. In this case, the one normal gene provides enough information to make some pigment, and the child has normal skin and eye color. The child has one gene for albinism. About one in 70 people are albinism carriers, with one defective gene but no symptoms; they have a 50 percent chance of passing the albinism gene to their child. However, if both parents are carriers with one defective gene each, they have a one in four chance of passing on both copies of the defective gene to the child, who will have albinism. There is also a type of ocular albinism that is carried on the X chromosome and occurs almost exclusively in males because they have only one X chromosome and, therefore, no other gene for the trait to override the defective one.
Genetics on Albanism
Oculocutaneous albinism is generally the result of the biological inheritance of genetically recessive alleles (genes) passed from both parents of an individual for example OCA1 and OCA2. Some rare forms are inherited from only one parent. There are other genetic mutations which are proven to be associated with albinism. All alterations, however, lead to changes in melanin production in the body.[6][11] Some of these are associated with increased risk of skin cancer ( see list of such genetic variations).
The chance of offspring with albinism resulting from the pairing of an organism with albinism and one without albinism is low. However, because organisms (including humans) can be carriers of genes for albinism without exhibiting any traits, albinistic offspring can be produced by two non-albinistic parents. Albinism usually occurs with equal frequency in both sexes.[6] An exception to this is ocular albinism, which it is passed on to offspring through X-linked inheritance. Thus, ocular albinism occurs more frequently in males as they have a single X and Y chromosome, unlike females, whose genetics are characterized by two X chromosomes.[12]
There are two different forms of albinism: a partial lack of the melanin is known as hypomelanism, or hypomelanosis and the total absence of melanin is known as amelanism or amelanosis.
Treatments for Albinism
To date, there's no way to supplement melanin in people with albinism or to force the body to make it. Skin can't be darkened, and eye anatomy can't be fully corrected. But hope is not lost. Treatments for albinism complications are readily available. Early visits to low-vision eye specialists can improve vision dramatically. Here's what they might prescribe
Work Cited
"What Is Albinism?" NOAH. N.p., 1995. Web. 4 May 2014. < http://www.albinism.org/publications/what_is_albinism.html>.
Sims, Judith L. "Albinism." Children Health. N.p., n.d. Web. 4 May 2014. < http://www.healthofchildren.com/A/Albinism.html>.
King, Richard A., et al. "Facts about Albinism." International Albinism Center, University of Minnesota. http://www.cbc.umn.edu/iac/facts.html>
Nasr, Susan L. "How Albinism Works." N.p., n.d. Web. 4 May 2014. < http://health.howstuffworks.com/skin-care/problems/medical/albinism4.htm>.