Guan, Y et. al. EMBO Mol Med (2016) http://www.ncbi.nlm.nih.gov/pubmed/26964564
Hemophilia B is a genetic blood clotting disorder that results from a mutation in coagulator factor IX (FIX) normally treated through intravenous deliver of FIX. As an increase in FIX levels by as little as 1% can lead to significant clotting improvement, Hemophilia B is uniquely suited for gene therapy treatment. Guan et al. utilized the CRISPR/Cas9 system and homology-directed repair to correct the mutation in the FIX gene. While the HDR rate was found to be 0.56% efficient with a single-stranded DNA donor and 1.5% efficient with a double-stranded plasmid donor, the rate of repair was great enough to restore hemostasis.