“Using a previously undescribed approach involving single guide RNA, we successfully removed large genome rearrangement in primary cells of an individual with an X chromosome duplication including MECP2.”
Wojtal, D., Kemaladewi, D. U., Malam, Z., Abdullah, S., Wong, T. W., Hyatt, E., et al. (2016). Spell Checking Nature: Versatility of CRISPR/Cas9 for Developing Treatments for Inherited Disorders. American Journal of Human Genetics, 98(1), 90-101.
2015 and 2016 have already been marked by some major breakthroughs in potential steps toward treatment of MECP2 Duplication Syndrome. This report in the American Journal of Human Genetics definitely adds to collection.
CRISPR/cas9 technology is a relatively new and potentially powerful method for editing DNA. Clustered regularly-interspaced short palindromic repeats were first shown to have practical application for editing DNA in 2012. Its potential for treating gene duplications such as MECP2 duplication seemed obvious. Nevertheless, the steps necessary to get from a general demonstration of potential value to an actual treatment were many and the potential for hitting a roadblock along the way seemed high.
This new study goes a long way toward the goal, and applies the technology directly to MECP2. Of course there is a long way to go, but this is a big and very encouraging step forward. This only removed the duplication in some fibroblast cells used in the study. Nevertheless, it is the first time someone can say the duplication was removed and the DNA was actually repaired.
We were able to detect a loss ofthe amplicon specific to the duplicated region and an accumulation of the amplicon corresponding to a single WTcopy, demonstrating that the entire duplication was successfully removed after treatment