Will Down's syndrome be ever reversible?

Question

Down syndrome is caused by genetic disorder when in DNA chromosome #21 has three copies (instead of 2 copies). If I understand correctly then the Genetic Engineering is the closest field in modern medicine that studies how to alter host's DNA.

Would there in next few years be a cure for Down's syndrome (i.e. remove the third copy of chromosome #21 in an adult's DNA)? If not, then what are difficulties that would still need to be overcome in genetic engineering to do something like that?

For example, is it impossible to consistently change DNA for all cells in body? Would these cells start to "attack" each other while being in partially reconfigured state?). If I understand correctly then CRISPR* method is the new tool in genetic engineering that may allow to do such DNA manipulations?

P.S. as it may be obvious from my question I don't have medical background and my questions is motivated by having relative affected by Down's syndrome.

P.P.S. I found this link http://www.prnewswire.com/news-releases/new-down-syndrome-therapy-discovered-300135102.html - not sure how to interpret it.

Answer 1

Reversing Down Syndrome in adults is not something being currently researched to my knowledge. Alerting the DNA throughout the body of a person at this point is purely science fiction, but even if it were possible the critical structures that were created due to the genetic mutation wouldn't just go away.

Take the simian crease in the hand of many with down syndrome. If you altered the DNA of the entire person they'd still have the simian crease because it was established early in the early formation of the person as an embryo. The genes for creating a hand aren't re-expressed later.

More importantly, many of the brain structures and pathways are formed in early childhood and puberty and a genetic change after then would have little effect.

Genetic alteration research would first be focused on embryonic intervention, but in not aware of any studies actively looking at that even. Most research is focused on early detection, causes/prevention, and therapeutic intervention for mitigation of symptoms. You can see none of the studies currently being conducted by the National Down Syndrome Society or the International Mosaic Down Syndrome Society are related to genetic intervention. These may also give you a feel for the type of research (here, here, and here).