Adeno-associated virus vector delivery method in gene-editing is not safe – it inserts the vector including the bacterial nuclease in the genome

In gene-editing therapies, delivery of the “drug” (the enzyme – ZFN/Cas9/TALEN) to the cells is a key problem. Often, they are packed into a stripped off virus (AAV). It is generally assumed to be episomal, ie it stays outside the genome (and will probably fade away with time as the cell replicates)

It is long known (2003) that AAVs “vectors integrate at chromosome breakage sites“, but dont create breaks.

To add a nuclease, which creates breaks, to AAV is a toxic cocktail.

Several (N=12 till date)  show that the Cas9 gene is inserted in the genome (as is the AAV genome, which is another controversial issue concerning Hepatocellular carcinoma regarding this method) – or there are translocations.

So, possibly all patients in these ZFN trials have the zinc finger protein and the FokI-nuclease integrated in their genomes. Here is data from ZFN.

These are CRISPR-trials

Here is one example where the Cas9 (17 aa peptide – IKDWILMDENYEFCFSL) inserts in the Vegfa gene in this study. 

 

Here is table showing number of AAV and Cas9 reads..

 

Here is list of studies where I could not find data (please let me know if you do). 

Many of them are DMD related.