| GENE THERAPY |
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Gene therapy is not a classical routine therapy as nowhere worldwide is being prescribed. All the treated patients are actually members of clinical trials with some inclusion criteria. Gene therapy aims to alter a pathological phenotype and the reconstruction of a physiological one. What kind of genetic material is needed, in which cells and how exactly should be used depends on the kind of the disease and the appropriate technology. Gene therapy has to do with all the pathological conditions having to do with the genetic material. These conditions could be hereditary (single gene with mendelic inheritnce) or non-hereditary genetic diseases (such as cancer), even multifunctional diseases (Parkinson's disease). In all cases the gene transfer should be performed to the somatic and not the germ cells.
Ι. Gene addition, or gene replacement, or gene augmentation. Implantation of a "physiological" gene in the appropriate cells, while the mutant allele is still present. In general, it has to do with genetic diseases due to mutations which eliminate the functionality of a protein in the cell (loss-of-function).
This strategy aims to inactive the translation of a gene whose product is harmful for the cell and it's being used in: (α) conditions caused by mutations translated in nonfunctional proteins, (β) malignancies caused by the hyper expression of proto-oncogenes or the expression of non functional proteins. This could be done using anti-sense oligonucleotides, siRNAs (small interfering RNAs) or ribozymes.
This strategy has to do with the correction of mutations through the alteration of the genotype. This is the most recent approach by the use of zinc-finger nucleases (ZFNs), which corrects the DNA in specific sites. Ι. Transfer of a gene not physiologically expressed in the specific cells. This strategy is usually used for the treatment of cancer cells, transferring a gene coding for a toxin.
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