Gene TherapyGene Therapy

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What is gene therapy?What is gene therapy?

It’s an experimental science used to help treat and prevent diseases by introducing DNA/RNA into a person’s cells.

Approaches -Turning off mutated genes -Make diseased cells more evident so that immune sys’t will recognize them as intruders and attack

-Replacing missing or mutated genes

It’s an experimental science used to help treat and prevent diseases by introducing DNA/RNA into a person’s cells.

Approaches -Turning off mutated genes -Make diseased cells more evident so that immune sys’t will recognize them as intruders and attack

-Replacing missing or mutated genes

How do genes get delivered into a cell?

How do genes get delivered into a cell?Vectors: viruses -in vivo and ex vivo

Types of viruses retroviruses Adenoviruses Adeno-associated viruses

Vectors: viruses -in vivo and ex vivo

Types of viruses retroviruses Adenoviruses Adeno-associated viruses

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Non-viral gene delivery

Non-viral gene delivery

Direct intro of therapeutic DNA into target cell, however it’s limited to certain tissues

Chemically linking DNA to a molecule that will bind to special cell receptors

Experimenting with intro of 47th chromosome into target cell. It would be a large vector carrying large amount of genetic code

Direct intro of therapeutic DNA into target cell, however it’s limited to certain tissues

Chemically linking DNA to a molecule that will bind to special cell receptors

Experimenting with intro of 47th chromosome into target cell. It would be a large vector carrying large amount of genetic code

Current Status of Gene Therapy

Current Status of Gene Therapy

Available in clinical trials

1999-suffered major setback with the death of 18 yr.old Jesse Gelsinger

He was participating in a trial for ornithine transcarboxylase deficiency (OTCD).

Died from multiple organ failures believed to be triggered by immune response to adenovirus carrier

Available in clinical trials

1999-suffered major setback with the death of 18 yr.old Jesse Gelsinger

He was participating in a trial for ornithine transcarboxylase deficiency (OTCD).

Died from multiple organ failures believed to be triggered by immune response to adenovirus carrier

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Cont’dCont’d In 2003 the FDA placed a temporary halt on gene therapy trials using retroviral vectors in blood stem cells

The 2nd child treated in a French gene therapy trial had developed leukemia like symptoms

Treated for X-linked combined immunodeficiency disease (X-SCID) known as “bubble baby syndrome”

In 2003 the FDA placed a temporary halt on gene therapy trials using retroviral vectors in blood stem cells

The 2nd child treated in a French gene therapy trial had developed leukemia like symptoms

Treated for X-linked combined immunodeficiency disease (X-SCID) known as “bubble baby syndrome”

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RisksRisks Immune response to newly introduced viruses

Possibility that once inside the body viruses may recover ability to cause disease

Gene therapy considered short-lived

target cells must remain functional

Cells containing therapeutic DNA must be stable

Difficulty treating diseases caused by the combined effects of variations in genes

Immune response to newly introduced viruses

Possibility that once inside the body viruses may recover ability to cause disease

Gene therapy considered short-lived

target cells must remain functional

Cells containing therapeutic DNA must be stable

Difficulty treating diseases caused by the combined effects of variations in genes

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Ethical ConsiderationsEthical Considerations Who decides which traits are normal and which constitute as a disability or disorder

Is somatic gene therapy is more or less ethical than germ-line therapy?

Religious view: Is it right to manipulate genes as if playing God?

Science is a response to proper human activity reflecting in some part God’s wisdom and creativity

Who decides which traits are normal and which constitute as a disability or disorder

Is somatic gene therapy is more or less ethical than germ-line therapy?

Religious view: Is it right to manipulate genes as if playing God?

Science is a response to proper human activity reflecting in some part God’s wisdom and creativity

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Somatic Gene TherapySomatic Gene Therapy

Directed at the body’s non-reproductive cells and only affects the genetic makeup of one person

Few ethical considerations

Directed at the body’s non-reproductive cells and only affects the genetic makeup of one person

Few ethical considerations

Germ-line Gene TherapyGerm-line Gene Therapy Targets egg and sperm cells, therefore the insertion of the gene passes on to next generation

Genetic modification of early embryos-

• Those who think early embryos are like a human person say NO to germ-line

• Those who think that in later development human acquire trait that make them human subjects say YES to germ-line

Targets egg and sperm cells, therefore the insertion of the gene passes on to next generation

Genetic modification of early embryos-

• Those who think early embryos are like a human person say NO to germ-line

• Those who think that in later development human acquire trait that make them human subjects say YES to germ-line

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Other ConsiderationsOther Considerations Possibility for genetic enhancement

Gene therapy is expensive and its use with IVF makes it unlikely that the costs will be covered by insurance companies, thus making people of means have better access

Possibility for genetic enhancement

Gene therapy is expensive and its use with IVF makes it unlikely that the costs will be covered by insurance companies, thus making people of means have better access

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My Opinion !My Opinion ! May be the only way to treat certain problems Ex: treat genetically determined tumors like retinoblastoma

“Far more efficient to cure a genetic disease with a single treatment that will prevent its appearance in future generations, than to treat the disease each time it appears, generation after generation”

Conserves future health care resources

May be the only way to treat certain problems Ex: treat genetically determined tumors like retinoblastoma

“Far more efficient to cure a genetic disease with a single treatment that will prevent its appearance in future generations, than to treat the disease each time it appears, generation after generation”

Conserves future health care resources