ABOUT ALBINISM

What is physically different on the chromosomal level about an individual with albinism? Why and how did this occurr?

Ocular albinism (OA1) or oculocutaneous albinism (OCA) are caused by a change in the GPR143 gene, which has a significant role in the pigmentation of skin. A mutation in this gene may result in a deregulation of melanocyte tyrosinase enzymes, which are the enzymes responsible for producing pigmentation. This change allows for a third OCA genotype. The genes for OCA are located on the autosomal chromosomes. Autosomes are the 22 pairs of chromosomes that contain general body characteristics. For a recessive trait such as OCA to occur the parents have to be carriers of the albinism trait, meaning both chromosomes from each parent must carry the trait. They are considered carriers because they carry a recessive gene but do not manifest the condition. The mother and the father have to have a family history of albinism even if they themselves have perfectly normal pigmentation; this is called autosomal recessive inheritance. Almost all people with ocular albinism are males because the gene is found on the X chromosome. This means that a male only needs to inherit one changed copy of the gene to manifest OA1. While it is possible for females to have OA1, it is extremely rare because both X chromosomes have to be changed. (Information Bulletin, 2015)

Can albinism be detected prenatally? If so, what method is used to detect it?

Albinism cannot be detected prenatally if the couple has not already had a child with albinism. Many attempted tests do not find all the possible DNA changes and are therefore inconclusive. (Information Bulletin, 2015). However, babies can be diagnosed before birth if a couple already has a child with a confirmed diagnosis of albinism by DNA analysis. This allows the doctors are able to figure out what mutation had caused the change in genes. A test called chorionic villous sampling can be done at 10 to 12 weeks of pregnancy where they remove part of the placenta to test the DNA. They can also remove cells from the amniotic fluid later on in the pregnancy to do further DNA testing, a method called amniocentesis. (Nasr, 2008). With these methods, cells in the fluid are examined to determine if the fetus has an albinism gene from each parent. Albinism is a rare disorder that occurs in all-racial and ethnic groups throughout the world. In the United States, approximately 18,000-20,000 people have some type of albinism. In some parts of the world, occurrence of albinism can be as high as 1 in every 3000 people. (Information Bulletin, 2015). And about 1 in 70 people carry a gene for OCA. (Draper, 2013)

What are the the physical/cognitive traits that an individual that albinism may have. Is the person born with these differences? Is there a progression of the disorder? What is the life expectancy of an individual with this disorder?

Albinism, at its essence is a genetic disorder where a person is born with is a defect of melanin production resulting in little to no pigment in the hair, skin and the iris of the eyes. Melanin is the natural substance that is responsible for providing pigment to the hair, skin and eyes and is produced by skin cells called melanocytes. In addition it also provides skin with protection again ultra-violet radiation from the sun (Habif, 2012). Due to the deficiency in melanin, people with albinism often have an absence of colour in their skin, hair and/or irises. Other symptoms include crossed eyes, light sensitivity, rapid eye movement and vision problems as well as functional blindness. Albinism is a disorder that a person is born with and does not usually affect lifespan, however a form of albinism called Hermansky-Pudlak syndrome (HPS) can shorten a lifespan due to the lung disease and/or bleeding problem that comes with it (Information Bulletin, 2015).