Extra Chromosome 21 Removed from Down Syndrome Cell Line

Scientists at the University of Washington have successfully removed the extra copy of chromosome 21 in cell cultures taken from a person with Down syndrome. A trimosy, which is having three copies of a chromosome, accounts for one fourth of pregnancy loss from miscarriages. Many diseases can also occur from a trimosy such as Edwards syndrome (trimosy 18), Patau syndrome (trimosy 13), and the most common in live births being Down syndrome (trimosy 21). The researchers used an adeno-associated virus to deliver a foreign gene TKNEO to chromosome 21. When grown under conditions that went against TKNEO, the cells best chance for survival was to lose the extra chromosome, which resulted in the deletion of TKNEO.


This method is not a treatment for Down syndrome but could possibly lead to cell therapies for blood-forming disorders that accompany Down syndrome. For example, patients with Down syndrome leukemia could have the trimosy corrected in lab-cultered cells  and then receive a transplant of their own stem cells without the extra chromosome. By being able to generate stem cells without trimosy 21, scientists may be able to get a better understanding of how problems associated with Down syndrome originate. The formation of trisomies is also a problem in regenerative medicine research using stem cells, and this new approach could prevent this from happening. One of the negative things that could result from gene therapy is gene toxicity. By removing a chromosome, there is a possibility that the genetic cody could break or rearrange, but researchers do not think that this method will result in that.

This removal of human trisomy could have both clinical and research applications. It gave researchers a better understanding and could have the potential to make many medical advancements when it comes to gene therapy. With trisomy being such a big problem in pregnancy loss and life long diseases, any information and discoveries could make such a difference in the medical world. It is amazing to see the ability of gene therapy and the results that can come from it.