19遗传疾病的治疗eng v(1).ppt

19 基因治疗 Gene Therapy
1. What is gene therapy?
Genes, which are carried on chromosomes, are the basic physical and functional units of heredity. Genes are specific sequences of bases that encode instructions on how to make proteins.
Although genes get a lot of attention, it’s the proteins that perform most life functions and even make up the majority of cellular structures.
When genes are altered so that the encoded proteins are unable to carry out their normal functions, ic disorders can result.
Gene therapy is a technique for correcting defective genes responsible for disease development.
Researchers may use one of several approaches for correcting faulty genes:
A normal gene may be inserted into a nonspecific location within the genome to replace a nonfunctional gene. This approach is mon.
An abnormal gene could be swapped for a normal gene through homologous bination.
The abnormal gene could be repaired through selective reverse mutation, which returns the gene to its normal function.
The regulation (the degree to which a gene is turned on or off) of a particular gene could be altered.
2. How does gene therapy work?
In most gene therapy studies, a "normal" gene is inserted into the genome to replace an "abnormal," disease-causing gene.
A carrier molecule called a vector must be used to deliver the therapeutic gene to the patient's target cells. Currently, the mon vector is a virus that has been ically altered to carry normal human DNA.
Viruses have evolved a way of encapsulating and delivering their genes to human cells in a pathogenic manner.
Scientists have tried to take advantage of this capability and manipulate the virus genome to remove disease-causing genes and insert therapeutic genes.