How Albinism Works
By Susan Nasr
Have you ever seen someone who has albinism? Sure, you have: Jeremy Reed in the 1995 movie, "Powder," with unmistakably white skin. Lightning struck his mother during pregnancy, enabling him to read people's thoughts. But as you might have guessed, albinism is a physical, not a supernatural, condition. Let's leave Hollywood and enter the lab and clinic to separate fact from fiction.
What, exactly, is albinism? Albinism is a collective term for many loosely related conditions. Everyone with albinism makes less than the normal amount of the pigment melanin. In order to understand how albinism works, you must first understand how melanin works.
We make melanin in specialized cells. Melanin colors our eyes, skin and hair. Since it can absorb every wavelength of light, melanin protects our skin from damage by the sun's ultraviolet rays. It also helps our eyes develop and handle visible light properly. In those with albinism, the amount of melanin made ranges from none to almost the normal amount. This can affect appearance -- without melanin, hair and skin are both white. However, a person with slightly reduced melanin may look just like his unaffected parents and siblings [source: Oetting]. Doctors often diagnose albinism using an eye exam. Since melanin plays a part in eye development, people with albinism universally have unusual eye anatomy and less-than-perfect vision. Albinism isn't contagious, so you can't catch it. It's caused by a mutation in DNA, passed from parents to child, present at birth. In albinism, the mutation can happen in three areas:
- The recipe for melanin
- The proteins that make melanin
- The parts of the cell that package and distribute melanin
Albinism has been documented around the globe, in many ethnic groups [source: Roy]. Yet, it is a rare condition. One in 17,000 people worldwide has a form of albinism [source: Gronskov]. Certain forms are more common in certain populations. The most common form of albinism, OCA2, is found in one in 36,000 Caucasians in the United States [source: Gronskov], but in one in 125 Kuna Native Americans in Panama [source: Roy].
Albinism is so much more than pale skin, hair and eyes. In this article, find out the simple "manufacturing problem" responsible for albinism, why people with albinism sunburn on cloudy days, why sunglasses are more than an easy way to look cool for them, and more.
In the next section, we will discuss how the cellular recipe for melanin goes awry in people with albinism. What goes wrong, and where?
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