What is the Difference Between Somatic and Germline Gene Therapy?

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The main difference between somatic and germline gene therapy lies in the types of cells they target and the heritability of the introduced genetic changes.

Somatic gene therapy involves the transfer of a desired gene to a somatic cell, which is any cell other than gametic cells, undifferentiated stem cells, or gametocytes. These cells do not produce sperm or eggs, so the gene is not transferred to the offspring. The effects of somatic gene therapy are limited to the treated individual and are not passed on to their children. This type of gene therapy has been tested and implemented for a longer time, with the first trials occurring two and a half decades ago.

Germline gene therapy, on the other hand, involves the introduction of a desired gene in germ cells, such as sperm or eggs. The gene gets transferred from one generation to another generation, meaning that the genetic changes can be inherited by the patient's children and subsequent generations. Germline gene therapy has a greater impact and is less established than somatic gene therapy, which merits more caution and regulatory scrutiny.

In summary:

  • Somatic gene therapy targets body tissues and does not pass genetic changes to offspring.
  • Germline gene therapy targets germ cells and passes genetic changes to offspring and future generations.

Comparative Table: Somatic vs Germline Gene Therapy

Here is a table comparing the differences between somatic and germline gene therapy:

Feature Somatic Gene Therapy Germline Gene Therapy
Definition Somatic gene therapy refers to the introduction or alteration of genes in somatic cells. Germline gene therapy refers to the introduction or alteration of genes in germ cells.
Type of Cells Involved Somatic cells (non-reproductive cells). Germ cells (reproductive cells like sperm and egg cells).
Reproducibility Alterations made in somatic cells are not inherited by the next generation. Alterations made in germ cells can be inherited by the next generation.
Uses Somatic gene therapy is used for treating various genetic disorders by altering the genes responsible for the disease. Germline gene therapy is used for treating genetic disorders such as ADA deficiency, PNP deficiency, and Lesch-Nyhan Syndrome.
Ethical Considerations Fewer ethical considerations as alterations are not inherited by the next generation. More ethical considerations due to the potential for alterations to be inherited by future generations.

Both somatic and germline gene therapies involve altering defective genes or introducing new genes to target the cause of a disease. However, they differ in the type of cells involved, the reproducibility of the alterations, and the ethical considerations associated with each therapy.