Wednesday, November 24, 2010

Syndrome Gives Blacks Blue Eyes

A recent commenter on this blog suggested that the blue-eyed Black boy, in an earlier post, may present Waardenburg Syndrome, a rare autosomal genetic disorder that has possible bright blue eyes as one of its qualifying criteria, along with possible deafness (common). Actually, the cause of the blue eyes is a form of albinism that may include patches of non-pigmented skin or forehead hair, regardless of ethnicity.

There are four types of Waardenburg Syndrome, with a mix of possible characteristics as the determinant. Medical challenges increase with type. The boy in the picture is displaying two major symptoms of type 1, as does the previous boy (perhaps) (here); bright blue eyes and dystopia canthorum, a condition where the inner corners of the eyes are set more widely apart, but with normally distanced eyes.

Waardenburg occurs once in every 42,000 births, and is a deficiency inherited from a single parent, who may or may not display similar characteristics. Regarding the eye, color abnormalities come in three forms; heterochromia (multiple colors), bilateral isohypochromia (pale blue eyes), or fundus (reflective) pigmentary alterations (spottiness).

So, besides naturally occurring genetic blue eyes in dark skinned people, as previously discussed, understanding Waardenburg's is another avenue of accurately recognizing phenotype (gene expression) in eye color.

James C. Collier

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9 comments:

Quito said...

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Eye Glasses San Francisco said...

Thanks for sharing about Waardenburg. Where can I get more information about the blue eyes?
Can you help me out in this if possible? Thanks in advance.

Mindy said...

The boy in that picture looks stunning with blue eyes. Thankyou for the information, very interesting to know.

Mikie said...

Blue eyes are not a form of albinism, it's a genetic mutation traced back to 6000-10,000 years. It's caused by a restriction on the amount of melanin, the pigment that gives colour to our hair, skin and eyes. Albinism is caused by the destruction, or complete block on one or more genes that contribute to our bodies melanin production, causing the body to produce no melanin at all. There's a really interesting article I found not to long ago about the origin of blue eyes: http://www.sciencedaily.com/releases/2008/01/080130170343.htm

Anonymous said...

@mikie, the thing is blacks dont usually get blue eyes even though they have non black relatives with them. when blacks have blue eyes its usually a "defect". but i dont see how thats a defect, he literally looks like the personification of an angel.

ZaCloud said...

@Mikie, there's such a thing as ocular albinism, where only the eyes are deprived of pigmentation while the rest of the body has pigment. Look it up for more details.

Anonymous said...

Blacks can have blue eyes. I'm tired of people saying that. Just because blacks are born with a beautiful feature it has to be a defect. Are whites just that ignorant to admit blacks are beautiful and can be born with beautiful features. I have a black friend girl with beautiful natural blonde curly locks and whites always ask her is she mixed and when said "no" they are shocked and insist some form or fashion she is. While UN reality both of her parents are black!
I'm sorry but this touches me because I am a african american women and my eyes are bluish/Grey. Very light in color and I've went through my whole life with whites asking me am I mixed or do I have a "defect"! Its not only rude but it is offensive bc when I answer "no" they insist I do research as if I don't know my mom and dad ethnicity! Or as if I don't know I have/or don't have a defect.
I AM BLACK. AND PROUD. AND ON TOP OF THAT I HAVE THE MOST BEAUTIFUL ASTONISHING BLUE EYES AND SO DOES MY SON. I DONT CARE HOW CRAZY OR UNUSUAL THEY MAY LOOK CONTRAST TO MY BLACK SKIN, BUT THEY ARE MY GOD GIVEN GIFT. AFRICAN AMERICANS ARE UNIQUE we come in varies skin colors, shapes, sizes, we have varies hair colors/texture, & we have different eye colors. Get over it.

Anonymous said...

Eye color is genetic, though, and full blooded African people do not carry the blue-eyed gene. So, someone in your blood line had the blue eye gene (unless it was a mutation) so you probably have some distant ancestry from a blue eyed gene carrier of European decent.

It's called genetics.

Sciencelover said...

Yes it’s called genetics. Because it was full blooded African people who migrated from Africa to Europe thousands of years ago and who underwent a genetic mutation to adapt to the cooler climate that they were living in. Blue eyes to maximize the absorption of vitamin D from the sun as well as white skin. I hope that you are aware that we all derive from the same African ancestor. The Neanderthals did not survive as a separate species as did the descendants from our mitochondrial “eve “ from Africa. Further, the woman who posted above is African American which means that according to US statistics (ancestry.com, NIH, NCBI, 1000 Genome project) the average African American is 65 percent sub-Saharan African and 29 percent European so when she said she was African American and proud I understood completely. We all are descendants of an African. Every person on earth can trace his or her lineage back to a single common female who lived 200,000 years ago in Africa. The other branch of human lineage contains African lineage as well. That is precisely why when DNA testing is conducted on humans there is always a tiny percentage of sub-Saharan DNA. I say all this to say first it is rare to find a “full blooded African” African American and secondly to point out that the blue eye gene is actually also an amazing genetic mutation that occurred 6,000 to 10,000 years ago so that humans would survive the substantial lack of sunlight in the north.