Gene Therapy

Question 1

Basics of gene therapy

Answer 1

• insert a functioning allele of a particular gene into a cell in which only non-functioning / mutated alleles of the gene exist
• this allows the cell to produce a functioning protein
• this individual no longer suffers from the genetic disorder associated with the non-functioning allele
• faulty allele is replaced / inactivated & new allele is inserted

Question 2

General issues with gene therapy

Answer 2

Question 3

What are the 2 types of gene therapy

Answer 3

Somatic cell gene therapy
Germ line cell gene therapy

Question 4

Somatic versus germ line cell gene therapy (differences)

Answer 4

Question 5

What is somatic cell gene therapy?

Answer 5

Functioning allele is inserted into body cells to replace a mutant allele
-> potential to help with a range of diseases, but treated cells have a limited life and individuals can still pass the disease to offspring (so temporary!)

Question 6

What is germ line gene therapy?

Answer 6

Inserting a healthy allele into the germ cells immediately after fertilisation
This means that the individual is born healthy
Issues = negative impact on individual e.g. designer babies? human rights vio?

Question 7

Which gene therapy can target specific tissues

Answer 7

Only somatic therapy

Question 8

What’s in vivo therapy?

Answer 8

The functioning allele is inserted via a vector into cells inside the body

Question 9

What is ex vivo therapy

Answer 9

The functioning allele is inserted via a vector into cells outside the body, therefore the body cells have been extracted

Question 10

Vectors insert the functioning alleles in gene therapy… these can be either (…) or (…)

Answer 10

Non-viral
Viruses

Question 11

An example of a non-viral vector is a liposome (sphere of lipid bilayer, e.g.to treat cystic fibrosis via gene therapy) how does this work?

Answer 11

Liposome containing functioning allele is placed into inhaler, sprayed in nose
Liposomes pass into the cell surface membrane of epithelial cells, lining the respiratory tract
-> nuclear envelope of host cells
The liposome inserts itself into the host genome, which expresses the protein

Question 12

What else can affect as a non-viral vector

Answer 12

Naked DNA

Question 13

What are issues with viruses as vectors?

Answer 13

May cause viral disease
May stimulate an immune response from the bodies immune system,
- body may develop immunity to the viruses, making subsequent deliveries more difficult

+ all the general issues with gene therapy