Translational considerations for CNS gene therapy.

Gene transfer is being rigorously evaluated in the laboratory in the preparation for the development of clinical therapies. Many CNS diseases, which have proved more challenging to treat than peripheral disorders, are prime candidates for gene therapy. However, there are numerous considerations in the development of gene therapy, including delivery, maintenance of expression, transgene level regulation, toxicity of the viral vector system and safety of the gene product. The authors review these issues and discuss various approaches used in preclinical studies. Alzheimer's and Parkinson's disease are employed as models, in which much research has already been performed, to address disease-specific questions about gene therapy approaches.