Physical Deformities in the Retarded/Mentally Handicapped

[Prince_James]

What is the genetic basis for the deformities often seen amongst those who are retarded/mentally handicapped? Do we know why they exhibit so many malshapen features?

 

[Hercules Rockefeller]

Many genes have developmental roles in multiple tissues during embryonic development.

 

[skaught]

Often times the chromosome that has to do with a certain mental aspect may also be a chromosome responsible for a certain physical characteristic. This accounts for the facial features of people with downs syndrome:

They may include a single transverse palmar crease (a single instead of a double crease across one or both palms, also called the Simian crease), an almond shape to the eyes caused by an epicanthic fold of the eyelid, upslanting palpebral fissures, shorter limbs, poor muscle tone, a larger than normal space between the big and second toes, and protruding tongue. Health concerns for individuals with Down syndrome include a higher risk for congenital heart defects, gastroesophageal reflux disease, recurrent ear infections, obstructive sleep apnea, and thyroid dysfunctions.

http://en.wikipedia.org/wiki/Down_syndrome

I believe this is because Down syndrome has something to do with the 21st chromosome. Which holds the info for all these characteristics

 

[Prince_James]

Fascinating stuff. Thanks for the info.

SO some of these disabilities, such as Down's Syndrome, effects an entire chromosome, not just a few genes on it?

 

[skaught]

Well actually, downs syndrome is a result of "the presence of all or part of an extra 21st chromosome."

What exactly this means, I am not sure. I think it means that some of the genes on the 21st chromosome are affected. I know that many genetic disorders can be results of damaged chromosomes, or loss/duplicates of chromosomes.

I traditionally try to avoid linking to wikipedia, but about a year ago I went ape shit reading about the various chromosomes and which chromosomes are resposible for what diseases. Entertained me for weeks! It just has a list of all 22 of them (and the 2 sex chromosomes) and what each one is responsible for.

http://en.wikipedia.org/wiki/Chromosomes

 

[Prince_James]

Thanks again. I shall pursue those topics.