Monday, April 12, 2010

Medical Mondays: Achondro-what?

Today's question comes from Elizabeth Arroyo (check out her blog Chandara Writes) who has a question about dwarfism: what are the causes, the physical attributes, and how does genetics play a role (for example, is it common in children whose parents might have close blood ties)?

So first we start with an art lesson.



The painting from 1656 by Diego Velasquez is entitled "Las Meninas" (The Maids of Honour). It is one of the most influential works in Western art history. The two figures to the far right have achondroplasia.

Achondroplasia (pronounced Ay-kondro-play-zha) is a genetic disorder that occurs in about 1/25,000 people. It's caused by a malfunctioning gene (FGFR3) that's needed in normal bone growth.

In order to have the condition, you need to have one gene. Having two genes is not compatible with life; babies that inherit two genes usually die in utero or after birth. Those that inherit one gene get the condition.

So if two parents both have achrondroplasia, then if they get pregnant, they have a 25% chance of having a child that will die; a 50% chance of having a child with the condition; and a 25% chance of having a totally normal child with no gene at all.
If only one parent has achrondroplasia, then the children have a 50% chance of being normal, and 50% chance of having achrondroplasia. None will die from inheriting two genes.

What if two parents were closely related, like brother and sister? In this case, their chances of having a child with the same disorder is the same if they were unrelated parents with achondroplasia.

Also, almost 80% of cases occur spontaneously because of a new genetic defect that happens for no reason. But those people can pass on the gene to their children.

So what kinds of traits do people with achondroplasia have? On average, men grow to about 4 ft 3 inches; the women 4 feet. The usually have bowed legs, large skulls for their size and facial features that are very similar. Just like in the painting above. Their arms and legs are short in proportion to their torso. Their fingers are usually short. Intelligence wise, they are completely normal. They have a life expectancy that's pretty long, although about 10 years less than an average adult.

Please keep in mind this post is for writing purposes only and is not to be construed as medical advice!

If you've got a medical question, let me know! Post below or email me at


I will usually answer your question by email within a day or two, but post later so you don't have to wait a long time to get back to your WIP. All I ask in return is that you become a follower of my blog and post a link on your blog when I post. Easy peasy.

Also, don't forget to check out Mental Health Mondays at Laura's Blog!

16 comments:

lbdiamond said...

Nice post! You know, I really look forward to these every week! Thanks!

Tahereh said...

wow. another really cool post, lydia!! you're a wealth of information!! :D :D

(also: i got to see Las Meninas in Madrid! the painting is HUGE and naturally, AWESOME. hehe)

thanks for sharing!!

Talli Roland said...

Interesting stuff, Lydia! Thanks for the info.

Shannon O'Donnell said...

You are brilliant! :-)

Lindsay (a.k.a Isabella) said...

Cool post. I love learning these new things:)

Jana Hutcheson said...

Interesting, as always! You must be so smart! :)

E. Arroyo said...

Thanks for the info.

Deb Salisbury said...

Great post! I've been toying with using a character with dwarfism. Thanks for the info!

Lydia Kang said...

Glad you find it useful Deb!

India Drummond said...

Great post... I didn't know a lot of this.

Michelle McLean said...

very interesting. And I've always liked that painting :)

Emily Ann Benedict said...

I love Medical Mondays. You've got some really facinating information. :)

~Nicole Ducleroir~ said...

What a fascinating post! My writer's mind was spinning: A pair of adults with Achondroplasia have a child, who is born without the condition...Interesting scenario, n'est ce pas?

Thanks, Lydia!

Sandy Shin said...

This is such a fascinating post! Reading these definitely makes me want to attend medical schools so I can have all these wealth of awesome knowledge. :D

Ee Leen Lee said...

ahh i thought that painting looked familiar.

fascinating post, I remember a CSI:Las Vegas episode dealing this.

Kirsten Lesko said...

Interesting post. I love that painting - how the little girl is the only one looking at the painter.

Thanks for the cool info!

 
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