Name: 為什麼有些人是白化病？ (Why Are Some People Albino?)
Uploaded: 2021-01-14T05:38:26.000Z
Duration: 3 min 26 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

Albinism is a rare genetic condition where a person’s body isn’t able to make skin

color. But what exactly is albinism and how common is it?

Albinism is a genetic condition, where a person’s body isn’t able to make pigments, so people

with this condition have white skin and hair, with light blue or pink eyes.

Albinism is a complex disorder. You get your skin, eye and hair color from melanin, which

is distributed through a number of genes but if one of these genes carry a certain mutation

the amount of melanin that is distributed throughout your body changes. Or sometimes

this mutation will keep your body from producing any melanin at all.

Melanin is produced by cells called melanocytes which are mostly found in your skin and eyes

but also in your hair. People with darker skin have a higher concentration of melanin

in their skin as opposed to fair skinned people. Albinism is the absence of melanin completely.

And it’s not just people, any animal with pigment can be albino.

Albinism is passed down genetically. In most cases, there is someone in the family tree

who also has the condition. But not all cases are the same. There are actually many types

of albinism that all affect a different gene mutation.

Oculocutaneous albinism, which is when it affects your eyes, skin and hair, ranges from

type 1 to type 4 with varying degrees of melanin impact and affects 1 in every 20,000 people.

The most severe version of albinism is oculocutaneous albinism type 1 or OCA 1.

OCA 1 is caused by a mutation in 1 of 4 genes. It’s characterized by having pink or white

skin, eyes and hair. Some babies born with OCA type 1 do develop slight pigmentation

during their early childhood but many born with this type of albinism never do.

OCA type 2 is less severe than type 1, skin and eye color will be pale but hair color

is more likely to be red, yellow or auburn.

OCA type 3 mostly affects people who are darker skinned and will create a reddish light tan

tone along with auburn eyes. OCA type 4 is very related to type 2, it’s hard to diagnose

which type of albinism is at work and is best left to genetic testing.

Another type of albinism is ocular albinism type 1 (OA1), also called Nettleship-Falls

syndrome. Much like its name suggests only the eyes are affected by the genetic mutation,

while hair and skin will remain the same. This happens only when the genetic mutation

of an x chromosome is inherited so it occurs mostly in males. The eyes will appear blueish

pink, the iris is super translucent and the most important part of the eye - the fovea,

which is responsible for a sharp image - does not develop properly. However any degree of

albinism comes with vision problems which include being cross eyed, being sensitive

to light, rapid eye movement and functional blindness.

An estimated 1 in 20,000 people worldwide are born with it and affects about 20,000

people in the U.S. every year. OCA type 2 happens more frequently in African Americans,

Native Americans and in Sub-Saharan Africa. Nigeria has one of the highest prevalence

of Albinism in the world with over two million people affected.

There are many myths that surround albinism and why it happens. While it is true that

people with albinism can’t tan and many can get very serious sunburns, the chances

of getting skin cancer is just as high with anyone else who spends a lot of time in the

sun. Other myths include the belief that albinos posses magic traits or bring bad luck. Some

tribal communities in Africa persecute them, forcing them to leave their native communities

or be killed. Places like Tanzania are having an especially hard time controlling this myth,

where sacrifices and the belief that albino body parts bring good luck causes a spike

So do you have albinism? Know someone who has it? Tell us your story down in the comments