Monday, April 27, 2015

'Editing' mitochondrial disease DNA.

illustration of cell structure

Mitochondrial DNA is passed exclusively through maternal inheritance and therefore, so are any diseases that are contained within mitochondrial DNA. These diseases cause a variety of severe conditions that currently have no cure. The risk of mitochondrial diseases being transferred from the mother to the child can be slightly reduced with genetic screening of the embryos, but there is a limit to therapeutic options. There is a new technique called mitochondrial replacement therapy, in which healthy mitochondria are provided from a donor, and this is currently under evaluation in the United States. Of course, with all unnatural editing of living organisms, there have been a lot of ethical, safety and medical objections. The Salk Institute has trialed an alternative approach in mice, which involves editing the mutated DNA using enzymes called restriction endonucleases and transcription activator-like effector nucleases (TALENs). Because this does not need a donor, the researchers believe that this technique is safer, simpler and more ethical. These enzymes are designed to make a precise incision that destroys the specific mutated DNA sequences and leave the normal mitochondrial DNA intact. The research team says that this has been effective in their mouse model, with the embryos growing to have healthy offspring of their own. 

With everything, there will always be those people who oppose it. However, is it really better to allow for someone to live a life with certain diseases that could cause painful deaths than have the possibility of destroying these diseases before the individual is born? It's understandable the ethics, with the chance of killing the embryo and the emotional conflicts of the parents, especially the mother, but there is good that could come of these things too. People want a cure after the fact, but when there's a possibility of getting rid of the problem before it starts, no one is for that. Maybe one day there will be ways to go about these things that do not have to many ethical implications. 

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