A ‘precision’ gene therapy turns out to have significant off-target effects
Dr. Mae-Wan Ho, Isis Press Release
Collateral damage from ‘precision’ gene therapy
A gene therapy technique, hailed as 2002’s ‘breakthrough of the year’ in its ability to shut down specifically and precisely any chosen gene, has been found not to be so specific or precise after all. The technique involves RNA interference (“Subverting the genetic text”, SiS 24 ), the ability of a short specific duplex sequence of RNA to target the transcript of gene, thereby shutting it down. Unfortunately, there are “off-target” effects on other genes and proteins.
The technique depends on a perfect match between the siNA (small interfering RNA) introduced and its complementary sequence in the gene transcript. Only sequences of 19-21 base pairs are generally used, as longer sequences induce nonspecific immune reactions.
However, various mismatches between the siRNA and its target appear to be tolerated, so that other transcripts with similar sequences are also affected.
Bron: I-SIS. 5-4-2005: Controversy over Gene Therapy ‘Breakthrough’