Gene editing has been all the rage in the medical world for the last few months. The last year scientists were talking about how it can help stop cancer. Now, they are saying it can also help treat muscular dystrophy.
The New York Times reports on the new information. Apparently, gene editing can seriously help treat Duchenne muscular dystrophy.
Researchers have been looking for a way to treat Duchenne muscular dystrophy for years. They say now, thanks to gene editing, they have finally made progress.
What is Duchenne muscular dystrophy?
“It is a progressive muscle wasting disease that affects boys, putting them in wheelchairs by age 10, followed by an early death from heart failure or breathing difficulties,” according to The Times.
What causes the disease?
It is caused by defects in a gene that encodes a protein called dystrophin, which is necessary for normal muscle function.
“The dystrophin protein plays a structural role, anchoring each muscle fiber to the membrane that encloses the muscle-fiber bundle. The dystrophin gene, which guides the protein’s production in the cell, sprawls across about 1 percent of the X chromosome and is the largest in the human genome,” according to The Times.
Since the disease is incurable and common for a hereditary illness, it has been a target for gene therapy for many years now. Scientists looked for a cure to no avail but were unsuccessful – until now.
“But gene therapy — the idea of curing a genetic disease by inserting the correct gene into damaged cells — is making a comeback. A new technique, known as Crispr-Cas9, let’s researchers cut the DNA of chromosomes at selected sites to remove or insert segments,” explains The Times.
Three different research groups (not working with each other) reported in the journal Science on Thursday that they had used the Crispr-Cas9 technique to treat mice with a defective dystrophin gene to test it out. Each team put in the DNA-cutting system onto a virus that infected the mice’s muscle cells, and excised from the gene a defective stretch of DNA, called an exon.
The Times reports, “Without the defective exon, the muscle cells made a shortened dystrophin protein that was nonetheless functional, giving all of the mice more strength.”
Scientists led the different research teams from Duke University, University of Texas Southwestern and Harvard University. Each team has applied for a patent.
The dystrophin gene has 79 sections (exons), but researchers have found that if they can remove some of them then the gene can function normally. Researchers want to remove the damaged exons to prevent the disease.
Researchers found that with Crispr-Cas9 editing, they could take out the 45th to 55th exons of the dystrophin gene from Duchenne patient cells grown in laboratory cultures. With the damaged exons removed, the cells started to engender dystrophin proteins.
The Times reports, “If a gene therapy for muscular dystrophy can be developed, it will compete with the antisense oligonucleotide drugs that are already in clinical trials. These work on the same principle of avoiding damaged exons, but instead of cutting them out of the DNA, they force the exons to be skipped at a later stage of the protein manufacturing process.”