Gene Therapy

Question 1

Gene supplementation

Answer 1

Adding one or more copies of a normal allele to a cell without removing pre-existing ones. The added alleles are dominant and mask the effects of the pre-existing recessive alleles.

Question 2

Germ-line gene therapy

Answer 2

Sperm or egg cells are treated with new alleles so that all the offspring will function normally. Currently seen as unethical, not practiced on humans.

Question 3

Somatic cell gene therapy

Answer 3

Altering some but not all of the body cells. Not passed on to future generations. Used in treating CF

Question 4

Cystic Fibrosis

Answer 4

Affect the epithelial cells as a result of a recessive allele of a gene which controls the production of CFTP. Mainly affects the lungs and trachea producing overly thick mucus making breathing difficult and breeding bacteria.

Question 5

Treating CF with gene therapy

Answer 5

The aim is to replace the recessive alleles in the lung cells with normal ones so that they can produce normal CTFP. The vector is usually liposomes, carrying the DNA for making healthy CFTP.
These modified cells eventually die and the treatment must be repeated

Question 6

Gene replacement

Answer 6

Replacing a defective allele with a normal one