And isn’t this an interesting thing:

http://www.scientificamerican.com/article/down-syndrome-and-alzheimer-s-disease-have-a-lot-in-common/

“Is Alzheimer’s disease an acquired form of Down syndrome?”

And it’s not even April 1!

Consider me extremely skeptical. Down syndrome occurs through the overexpression of at least seven (or fewer with partial trisomy) genes on Chromosome 21 by a factor of 1.5. Alzheimer’s isn’t.

However, most cases of early-onset Alzheimer disease are caused by gene mutations that can be passed from parent to child. Researchers have found that this form of the disorder can result from mutations in one of three genes: APP, PSEN1, or PSEN2. And the gene APP is on Chromosome 21. So there may be some overlap. PSEN1 is located on chromosome 14. PSEN2 is located on chromosome 1. So there’s no real similarity.

Isn’t DS caused by trisomy of the 21st chromosome?

Yes, trisomy 21 is the hallmark of Downs Syndrome.

buffy said:

Yes, trisomy 21 is the hallmark of Downs Syndrome.

Yes. As an aside, I recently went for my nuchal translucency scan which measures my chances of having a Down’s Syndrome baby. Based on my age alone, the chances are 1 in 235 (although different sources differ slightly). Based on measurements and blood tests, my risk decreased to 1 in 4700.

There is a new blood test available which has a 99% accuracy to assess one’s risk. The blood is taken here, sent to the US for testing and you get the results within about 10 days (at the moment it costs $700-$850 for this test). The scienticians extract the baby’s DNA from the mother’s to get the result.