maggie_82
07-17-2003, 1:15am
my sister's second daughter has albinism :sad:
if many of you dont know what that is that is ok nither did i but i looked it up so here is what it is
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 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. Often people do not recognize that they have albinism.
A common myth is that by definition 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.
Vision Problems
People with albinism always have problems with vision, and many have low vision. Many are "legally blind," but most use their vision for reading, and do not use braille. Some have vision good enough to drive a car.
Vision problems in albinism result from abnormal development of the retina and abnormal patterns of nerve connections between the eye and the brain. It is the presence of these eye problems that defines the diagnosis of albinism. Therefore the main test for albinism is simply an eye exam.
Types of Albinism
While most people with albinism have very light skin and hair, not all do. Oculocutaneous (pronounced Ock-you-low-kew-Tain-ee-us) albinism involves the eyes, hair, and skin. Ocular albinism involves primarily the eyes, while skin and hair may appear similar or slightly lighter than that of other family members.
Over the years researchers have used various systems for classifying oculocutaneous albinism. In general, these systems contrasted types of albinism having almost no pigmentation with types having slight pigmentation. In less pigmented types of albinism, hair and skin are cream-colored, and vision is often in the range of 20/200. In types with slight pigmentation, hair appears more yellow or red-tinged, and vision often corrects to 20/60. Early descriptions of albinism called these main categories of albinism "complete" and "incomplete" albinism. Later researchers used a test that involved plucking a hair root, and seeing if it would make pigment in a test tube. This test separated "ty-neg" (no pigment) from "ty-pos" (some pigment). Further research showed that this test was inconsistent, and added little information to the clinical exam.
Recent research has used analysis of DNA, the chemical which encodes genetic information, to arrive at a more firm classification system for albinism. Type 1 albinism (also called tyrosinase-related albinism) is the type involving almost no pigmentation. Type 1 albinism results from a genetic defect in an enzyme called tyrosinase. This enzyme helps the body to change the amino acid tyrosine into pigment. (An amino acid is a "building block" of protein, and comes from protein in the diet.) Type 2, a type with slight pigmentation, results from a defect in a different gene called the "P" gene.
Researchers have identified several other genes that cause forms of albinism. In one form of albinism, the Hermansky-Pudlak syndrome, there can be problems with bleeding, and with lung and bowel disease as well. Hermansky-Pudlak syndrome is a less common form of albinism, but should be suspected if a child with albinism shows unusual bruising or bleeding.
Genetics of Albinism
For nearly all types of albinism both parents must carry an albinism gene to have a child with albinism. Because the body has two sets of genes,a person may have normal pigmentation but carry the albinism gene. If a person has one gene for normal pigmentation and one gene for albinism, he or she will have enough genetic information to make normal pigment. The albinism gene is "recessive" — it does not result in albinism unless a person has two copies of the gene for albinism and no copy of the gene that makes normal pigment.
When both parents carry the gene, and neither parent has albinism, 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.
(The most common type of ocular albinism follows a different pattern of inheritance. The NOAH Information Bulletin "Ocular Albinism" has more information.)
Each parent of a child with oculocutaneous albinism must carry the gene. Both the father and the mother must carry the gene for albinism. For couples who have not had a child with albinism, there is no simple test to determine whether a person carries a gene for albinism. Researchers have analyzed DNA of people with albinism and found the changes that cause albinism, but these changes are not always in exactly the same place, even for a given type of albinism. Therefore the tests for the gene may be inconclusive.
if many of you dont know what that is that is ok nither did i but i looked it up so here is what it is
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 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. Often people do not recognize that they have albinism.
A common myth is that by definition 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.
Vision Problems
People with albinism always have problems with vision, and many have low vision. Many are "legally blind," but most use their vision for reading, and do not use braille. Some have vision good enough to drive a car.
Vision problems in albinism result from abnormal development of the retina and abnormal patterns of nerve connections between the eye and the brain. It is the presence of these eye problems that defines the diagnosis of albinism. Therefore the main test for albinism is simply an eye exam.
Types of Albinism
While most people with albinism have very light skin and hair, not all do. Oculocutaneous (pronounced Ock-you-low-kew-Tain-ee-us) albinism involves the eyes, hair, and skin. Ocular albinism involves primarily the eyes, while skin and hair may appear similar or slightly lighter than that of other family members.
Over the years researchers have used various systems for classifying oculocutaneous albinism. In general, these systems contrasted types of albinism having almost no pigmentation with types having slight pigmentation. In less pigmented types of albinism, hair and skin are cream-colored, and vision is often in the range of 20/200. In types with slight pigmentation, hair appears more yellow or red-tinged, and vision often corrects to 20/60. Early descriptions of albinism called these main categories of albinism "complete" and "incomplete" albinism. Later researchers used a test that involved plucking a hair root, and seeing if it would make pigment in a test tube. This test separated "ty-neg" (no pigment) from "ty-pos" (some pigment). Further research showed that this test was inconsistent, and added little information to the clinical exam.
Recent research has used analysis of DNA, the chemical which encodes genetic information, to arrive at a more firm classification system for albinism. Type 1 albinism (also called tyrosinase-related albinism) is the type involving almost no pigmentation. Type 1 albinism results from a genetic defect in an enzyme called tyrosinase. This enzyme helps the body to change the amino acid tyrosine into pigment. (An amino acid is a "building block" of protein, and comes from protein in the diet.) Type 2, a type with slight pigmentation, results from a defect in a different gene called the "P" gene.
Researchers have identified several other genes that cause forms of albinism. In one form of albinism, the Hermansky-Pudlak syndrome, there can be problems with bleeding, and with lung and bowel disease as well. Hermansky-Pudlak syndrome is a less common form of albinism, but should be suspected if a child with albinism shows unusual bruising or bleeding.
Genetics of Albinism
For nearly all types of albinism both parents must carry an albinism gene to have a child with albinism. Because the body has two sets of genes,a person may have normal pigmentation but carry the albinism gene. If a person has one gene for normal pigmentation and one gene for albinism, he or she will have enough genetic information to make normal pigment. The albinism gene is "recessive" — it does not result in albinism unless a person has two copies of the gene for albinism and no copy of the gene that makes normal pigment.
When both parents carry the gene, and neither parent has albinism, 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.
(The most common type of ocular albinism follows a different pattern of inheritance. The NOAH Information Bulletin "Ocular Albinism" has more information.)
Each parent of a child with oculocutaneous albinism must carry the gene. Both the father and the mother must carry the gene for albinism. For couples who have not had a child with albinism, there is no simple test to determine whether a person carries a gene for albinism. Researchers have analyzed DNA of people with albinism and found the changes that cause albinism, but these changes are not always in exactly the same place, even for a given type of albinism. Therefore the tests for the gene may be inconclusive.