ALBINISM

vicky s. wang

WHAT IS IT? Albinism is a defect of melanin production that results in little or

no color (pigment) in the skin, hair, and eyes.

Melanin is a skin pigment (substance that gives the skin its color). Dark-skinned people have more melanin than light- skinned people. Melanin comes in two types: pheomelanin (red) and eumelanin (very dark brown). Both amount and type are determined by four to six genes which operate under incomplete dominance

Melanin pigment

SYMPTOMS? A person with albinism will have one of the following

symptoms: Absence of color in the hair, skin, or iris of the eye Lighter-than-normal skin and hair Patchy, missing skin color

Albino bunny!

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ALBINO LION

A BRIEF HISTORY A man in the 17th century named Balthazar Telez, who was an explorer, came

up with the name "Albino", which means white negro, after he saw an albino African tribe. Balthazar thought he was seeing two different races of people. This was the first discovery of albinism.

The first ever reported case of albinism that scientifically came up was in the year 1908. Most of the individuals that have suffered from albinism have a long history of being ostracized and rebuked by society.

2 MAIN CATEGORIES Oculocutaneous

involves dilution of the color of the hair, skin and eyes most common form of albinism

Ocular melanin pigment mainly missing from the eyes while the skin

and hair appear normal or only slightly lighter accounts for 10-15% of all albinism cases

TYPES There are two main types of Oculocutaneous albinism:

Type 1 albinism is caused by defects that affect production of the pigment, melanin.

Type 2 albinism is due to a defect in the “P gene”. People with this type have slight coloring at birth.

The most severe form of albinism is called oculocutaneous albinism. People with this type of albinism have white or pink hair, skin, and iris color, as well as vision problems.

TYPE 1 Is cause by genetic defect of the tyrosinase enzyme that helps

the body to change the amino acid tyrosine into melanin pigment

OA1 Gene Mutations Associated with Ocular Albinism type 1

TYPE 2 Oculocutaneous albinism type 2 (OCA2) is an recessive

disorder characterized by defective melanin production of the skin, hair, and eyes, which is caused by mutations of the "P" gene.

The specific function of P has not been clarified, although it is likely to act as a transporter in the melanosomal membrane.

a melanosome is an organelle containing melanin

2 CATEGORIES

OCULOCUTANEOUS OCULAR

INHERITANCE Both are inherited in a autosomal

recessive manner

About 1 in 70 people have a gene for albinism. Couples whom are each carriers of the recessive albinism gene have a 1 in 4 chance of producing a child with albinism.

ASSOCIATED PROBLEMS Skin problems

Easily sunburn Increased chance of getting skin cancers

Eye problems Impaired vision: although not blind, vision is impaired and may

not be fully corrected with glasses. Varying degrees of near-sightedness or far-sightedness exist.

Photophobia: sensitivity to light or glare Nystagmus: involuntary movement of the eyes back and forth Strabismus: eyes do not fixate and track together Retinal involvement: this is an important area of the eye as it

is responsible for sending signals to the brain. Impaired transmission of signals causes various vision disorders

DIAGNOSIS AND TREATMENT Albinism can be diagnosed by observation of major or total absence of

pigmentation of the appearance of the skin, hair, and eyes. The most accurate way to determine albinism and its specific type is genetic

testing. This is helpful in families with albinism and is useful for specific, isolated populations who carry the trait in them.

Recently, a blood test has been developed that can identify carriers of the gene for some types of albinism.

There is no cure for albinism. Treatment is aimed to ease the symptoms and it depends on the extent of the disorder. Treatment of the eye conditions consists of visual rehabilitation.

BIBLIOGRAPHY Albinism. 15 6 2009. 25 3 2010 <http://dermnetnz.org/colour/albinism.html>.

definition of melanin. 3 26 1998. 24 3 2010 <http://www.medterms.com/script/main/art.asp?articlekey=4340>.

Fawn, Mike. Albinism- A History of Albinism. 25 3 2010 <http://ezinearticles.com/?Albinism---The-History-of-Albinism&id=1362804>.

Saitoh, Shinji. Oculocutaneous albinism type 2 with a P gene missense mutation in a patient with Angelman syndrome. 25 3 2010 <http://jmg.bmj.com/content/37/5/392.extract>.