Gene Therapy

Question 1

How does gene therapy work?

Answer 1

Genetic disorders are inherited disorders caused by abnormal genders or chromosomes e.g. cystic fibrosis
Gene therapy could be used to cure these disorders

Gene therapy involves altering alleles inside cells to cure genetic disorders
How you do this depends on whether the disorder is caused b a mutated dominant allele or two mutated recessive alleles
- if it’s caused by two mutated recessive alleles you can add a working dominant allele to make up for them
- if it’s caused by a mutated dominant allele you can silence the dominant allele (e.g. sticking a bit of DNA in the middle of the alleles so it doesn’t work anymore)

To get the new allele inside the cell, the allele is inserted into cells using vectors (e.g. plasmids)

Question 2

What are the two types of gene therapy?

Answer 2

1) somatic therapy
2) germ line therapy

Question 3

Somatic therapy

Answer 3

Involves altering the alleles in body cells, particularly the cells that are most affected by the disorder
E.g. cysts fibrosis is a genetic disorder thats very damaging to the respiratory systems, so somatic therapy targets the epithelial cells lining the lungs

Somatic therapy doesn’t affect the individual’s sex cells (sperm or eggs) so any offspring could still inherit the disease

Question 4

Germ line therapy

Answer 4

Involves altering the alleles in the sex cells
This means every cells of any offspring will be affected by gene therapy and they wont inherit the disease

Germ line therapy in humans is currently illegal though

Question 5

Positive ethical issues of gene therapy

Answer 5

• could prolong the lives of people with life-threatening genetic disorders
• better quality of life, ease the symptoms
• germ line therapy would allow carriers of genetic disorders to conceive a baby without that disorder

Question 6

Negative ethical issues of gene therapy

Answer 6

• potential to do more harm than good (e.g. risk of over expression of genders)
• expensive, so some people thing the resources can be better spent on their treatments that have passed clinical trials

Question 7

Disadvantages of gene therapy

Answer 7

• body could identify vectors as foreign, start an immune response against them
• allele inserted in the wrong place in DNA, possible causing more problems e.g. cancer
• effects of treatment may be short lived in somatic therapy
• patients might have to undergo multiple treatments with somatic therapy
• might be difficult to get allele into specific body cells