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3.4.7 Issues Particular to Genome Editing of Somatic Stem Cells

Recommendation The clinical use of genetically altered (including genome-edited) somatic stem cells should be reserved for the treatment or correction of severe disease and disability. Due to the inherent risks, these products should comply with established policies and regulations for genome editing and cell-based products. 

Potential clinical applications of genetically altered somatic stem cells should be evaluated for potential risks and benefits of serious medical diseases and conditions. Uses of genetic alteration for non-serious conditions or for enhancement of body performance or features, such as to give an advantage in sports, should be discouraged: the potential benefits are marginal and cannot offset the risks at this time; they are unlikely to have public support; and they could bring the field into disrepute. The current risks associated with the methods also make it inadvisable to use them in attempts to confer disease resistance.

The genetic alteration of cells provides a potential long-term/lifetime treatment for certain diseases. However, there are risks associated with this approach that include: 

  1. Off-target effects from the insertion of exogenous DNA in gene replacement applications.
  2. Incorrect on-target and off-target genetic events in genome editing applications.
  3. Large-scale chromosomal rearrangements/inversions due to multiple DNA cleavage events when using targeted nucleases in genome editing.
  4. Unwanted immune response to the virus or nucleic acids from the viral vector carrying the DNA or exogenous DNA.

A detailed discussion of these and other issues around clinical trials with genome-edited stem cells can be found in Appendix 5.