Gene Therapy

Uses:MONOGENEIC DISORDERS AND

COMPLICATED DISORDERS • Muscular dystrophy.• Cardiovascular diseases. • Block neurological disorders.• Eliminate infectious pathogens.

Gene therapy is an experimental technique used in treatment of malfunctioning genes, whereby a deficient or defective gene is replaced by a working gene.

Source: https://en.wikipedia.org/wiki/Gene_therapy

Germ line Gene Therapy Altering the genetic makeup of a gene of either an egg or a sperm cell before fertilization, or altering the genetic composition of a blastomere during an early stage of its division.

AdvantagesDisadvantages

cure is inherited

Error during the gene  'transplant'

Source: http://genmed.yolasite.com/

Somatic Gene TherapyAltering the genetic code or chromosomes of a person's somatic cells.

Advantages less controversial

Disadvantages use of viral vectors, is difficult.

GENE DELIVERY• Ex-vivo Adeno-virus or lenti. • In-vivo lenti-virus. (non-div)

Source: http://genmed.yolasite.com/

VECTORS USED IN GENE THERAPY • RETRO VIRUS.• ADENOVIRUS.• ADENO-ASSOCIATED

VIRUSES [AAVS].• HERPES SIMPLEX

VIRUS [HSV].• ALPHAVIRUSES. • VACCINA OR POX

VIRUSES.

Source: http://geneticmutationsgenetherapy.yolasite.com/

source: http://www.nature.com/

Retroviruses• First virus used as vector.• Reverse transcription.• Genome copies integrated into host by

integrase enzyme. • Zinc finger nuclease.• Gene therapy for SCID is vey much useful.

ADENOVIRUS

• with double stranded DNA genome that can cause respiratory, intestinal and eye infection.

• Don’t incorporated into host cell genetic makeup.

• Affect broader variety of cells.• Attacked by patient immune system, required

high quantity.• Used for treating cancer of liver and ovaries.

ADENO-ASSOCIATED VIRUSES [AAVS]

• Small, icosahedral, single-stranded DNA adeno-associated virus.

• Wild-type AAV contains a 4.7-kb.• 100 different capsids.• AAVs are small viruses from the Parvovirus

family with a genome of single stranded DNA.

HERPES SIMPLEX VIRUS [HSV]

• Human neurotropic virus.• HSV makes an ideal vector as it can infect a

wide range of tissues including muscle, liver, pancreas, and nerve and lung cells.

• Able to infect neurons which are not rejected by immune system.

Gene therapy vectors

• ALPHAVIRUSES • Pox virus • NON-VIRAL OPTIONS• Particles carrying the therapeutic gene are injected

intravenously and strong, high-gradient external magnets are used to capture the particles as they flow through the blood- stream.

MAGNETIC NANOPARTICLE-BASED GENE DELIVERY

Source: http://www.nature.com/

GENETIC DEFECTS

Source: http://images.wisegeek.com/

Source: http://japha.org/

Source: http://www.s-cool.co.uk/

Source: http://www.dailymail.co.uk/

Gene therapy for damage retinal cells

GENE THERAPY RISKS

• The gene therapy took triggered a chain reaction in his immune system, resulting in hepatic and respiratory failure, and consequently, his death four days after being treated.

• The genetically modified somatic cells decreased in amount. Because they are already differentiated and possess only a limited capability to multiply.