Gene therapy facts for kids
Gene therapy means putting in a working gene to a person who has a damaged gene. The European Commission has approved this method for one particular treatment. The treatment by the product Glybera uses a virus to infect muscle cells with a working copy of the gene. The European Commission has given Glybera marketing authorisation, which means it can be sold throughout the EU.
One in a million people have damaged copies of the lipase gene needed to break down fats. Fat builds up in their blood; this leads to pain and inflammation of the pancreas (pancreatitis). It is life-threatening. Up to now, the only way to manage the condition is to have a very low-fat diet.
When used in this way, a virus is a vector. That means it is a carrier; the gene has been inserted into the viral genome, and the virus sticks it into the human cells. The technique is called transfection. This technique is different from the gene knockout technique, which does not use a viral vector.
China was the first country to approve the commercial production of a gene therapy, in 2003. That gene therapy is for head and neck squamous cell carcinoma (HNSCC)—a cancer that occurs in 10% of new cancers in China. There are 2.5 million new cancer patients every year in China.
Sold under the brand name Gendicine, the world's first commercial gene therapy also uses a virus to insert the gene into the human genome.
The possibility of gene therapy was talked about as soon as the roles of DNA and RNA were known about. The first specific publication was in 1972.
Many more types of gene therapy are in the trial stage. It is clear that a cycle of events will be part of future clinical medicine: DNA sequence analysis > identify defective genes > fix genes with gene therapy or gene knockout. There are sometimes problems of side-effects; these may be discovered at the trial stage. There is now a database which lists all known clinical trials.
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A duplex of crRNA and tracrRNA acts as guide RNA to introduce a specifically located gene modification based on the RNA 5’ upstream of the crRNA. Cas9 binds the tracrRNA and needs a DNA binding sequence (5’NGG3’), which is called protospacer adjacent motif (PAM). After binding, Cas9 introduces a DNA double strand break, which is then followed by gene modification via homologous recombination (HDR) or non-homologous end joining (NHEJ).
Gene therapy Facts for Kids. Kiddle Encyclopedia.