6.3.8(Gene therapy)

Describe what is meant by gene therpay

• Inserting a functional allele of a particular gene into the cells that contain only mutated and non-functioning alleles of that gene.

• If the inserted gene is expressed, then the individual will produce a functioning protein

Name the 2 methods of gene therapy

• Somatic cell gene therapy

• Germ line gene therapy

Name 2 conditions which are treated by gene therapy

• Cystic fibrosis

• Huntington’s disease

Describe how somatic gene therapy treats genetic disorders

• A functioning allele is inserted into specific cells which lack the functioning allele

• This allows the cells to produce the protein which allows the cell to function properly

Name 2 methods of inserting the gene during somatic cell gene therapy

• Liposomes

• Bacteriophages

Describe how liposomes are used to insert the gene

• Alleles are packages within lipid molecules - liposomes

• They are sprayed into the airways of patients - they are inhaled and fuse with the plasma membrane of the lung epithelial cells

• They then enter the cell by endocytosis and the functioning gene is incoprated into the cells

Describe how a bacteriophage is used to insert a gene

• Harmless viruses are used as vectors to transport the allele to body cells

  • They carry a copy of the working allele into host cells without causing diseas

Describe the advantages of somatic cell line gene therapuy

• It could prolong the lives of people with genetic disorders and cancer

• It could give people with genetic disorders and cancer a better quality of life

Describe the disadvantages of somatic cell line gene therapy

• The effects of the treatment may be short-lived

• The patient might have to undergo multiple treatments

• It might be difficult to get the allele into specific body cells

• The body could identify vectors as forgien and start an immune response

• An allele could be inserted into the wrong place in the DNA

• An inserted allele could be over expressed, producing too much of the missing protein

• Disorders caused by multiple genes would be difficult to treat with this technique

Describe the advanatges of germ line gene therapy

• It could prolong the lives of people with genetic disorders and cancer

• It could give people with genetic disorders and cancer a better quality of life

• Carriers of genetic disorders might be able to conceive a baby without that genetic disorder or risk of cancer

• It could decrease the number of people who suffer from genetic disorders and cancer

Describe the disadvantages of germ line gene therapy

• It might be difficult to get the allele into specific body cells

• The body could identify vectors as foreign and start an immune response

• An allele could be inserted into the wrong place in the DNA

• An inserted allele could be over expressed, producing too much of the missing protein

• Disorders caused by multiple genes would be difficult to treat with this technique