Gene Therapy

Technique for correcting defective gene responsible for disease development.

A normal gene may be inserted into a non specific location within the genome to replace a non functional

An abnormal gene could be swapped for a normal gene through homologous recombination

The regulation of a particular gene could be altered

A carrier molecule called a vector must be used to deliver therapy gene

Most common vector is a genetically altered virus that carries human DNA

liposomes can also be used

IN- VIVO - direct injection of vectors

EX-VIVO - the removal and culture of cells which are subsequently modified gentically and returned to the individual

Cons - immune response, problems with viral vectors,multigenes disorders

Gene Therapy for Duchenne Muscular Dystrophy

Dystrophy occurs when a gene on X chromonsone fails to make an essential muscle protein 'Dystrohin'

begins in early childhood

inherited on X chromosone

susceptible to infections

defective phagocytes incapale of destroying harmful bacteria

transfusions of genetically altered stem cells - carrys missing gene

sucessfully transfered into bone marrow

other - repairs messenger RNA

introducing new genes

gene silencing

Thalassaemia - mutations in heamoglobin

slight exertion cause death and fatigue

Parkinsons disease - gene therapy 're-sets' cells

GAD is responsible for making a small molecule called GABA inhibits nerve cell activity

liposomes used

Huntingtons disease - Gene silencing

RNA interference

double - stranded RNA trigger the degradation of any other RNA in the cell with a matching sequence

If an siRNA is chosen to match the RNA - sopied from a gene

The gene for the enzyme sarcoplasmic reticulum CA inserted into a adenovirus vector

Delivered directly to the patients heart

High doses reduce cardiac symptons and improve heart functions