Gene Therapy Principle and Types What is gene

Gene Therapy- Principle and Types

What is gene therapy? • A technique for correcting defective genes responsible for disease development. • Altering a person’s genes in order to achieve a more desirable trait • A "normal" gene is inserted into the genome to replace an "abnormal, " disease-causing gene.

History of Gene Therapy • In 1970 s, proposed “gene surgery” for treating inherited disease caused by faulty genes. • In 1983, Scientists from Bayler College of Medicine in Houston taxas, proposed that “GT could one day be a viable approach for treating Lesch-Nyhan disease”.

• On sept. 14, 1990, a four-year old girl became the first person to undergo GT in US for treating ADA deficiency. • In the same year, GT was tested on patients suffering from melanoma, cystic fibrosis.

Gene therapy includes • Replacing a mutated gene with a healthy copy of the gene. • Inactivating a mutated gene that is functioning improperly. • Introducing a new gene into the body to help fight a disease

Administering Gene Therapy Successful gene therapy requires that: 1. Genetic nature of disease is understood. 2. The affected tissues are known and accessible. 3. Correct gene expression is achieved. 4. Harmful side effects if any are manageable.

Gene Therapy Principle AAV Nucleus Adenovirus Therapeutic Protein Retrovirus Naked DNA Target Cell

Types Of Gene Therapy n n Germ line gene therapy: Gene therapy can be targeted to germ (egg and sperm) cells. Somatic cell gene therapy: Gene therapy can be targeted to somatic (body cells).

Germline vs. Somatic • Modify sperm or egg cells. • Modify mature somatic cells. • The changes are • In somatic gene therapy, integrated into the DNA changes are not passed and passed on to future generations. • Not as common, very controversial. • This form is more common and has actually been used in humans.

Delivery Of Therapeutic Gene In Target Cells can be Delivered in two main ways: 1. First it can be delivered directly in to the body at the required site (In vivo). 2. Second it can be inserted in to cells from the affected tissue outside the body (Ex vivo)

In Vivo Gene Therapy v. Genetic material is transferred directly in to body of patient. v. Only available option for tissues that cannot be grown in vitro; or if grown cells cannot be transferred back. v More or less a random process v Requires an efficient and selective delivery system

Ex Vivo Gene Therapy

in vivo and ex vivo schemes EX VIVO IN VIVO

Thank you