CRISPR-Cas9 involves "editing out" specific DNA that may contribute to Alzheimer's, cancer or obesity
Scientists in China reportedly have used CRISPR-Cas9 on dogs and human embryos
What if you could literally edit your body’s genes?
Imagine taking specific genes out of your body to reduce your chances of becoming obese or getting diseases like cancer or Alzheimer’s.
A medical breakthrough like that would be historic. It would spare millions from pain and suffering. It would save society hundreds of billions of dollars in health care costs every year.
We’re talking about an unproven gene-editing technique called CRISPR-Cas9. It sounds like science fiction – until you learn that investors like Google and Bill Gates have contributed millions to help realize its potential.
Theoretically, the possible benefits of CRISPR-Cas9 could be nothing short of mind-blowing, including:
• Slowing the aging process and lengthening lives.
• Bringing back extinct species, like the woolly mammoth.
• Feeding the world by tweaking genes in farm crops so they’ll grow in more places.
CRISPR-Cas9 is based on a discovery that happened about a decade ago. Scientists realized that bacterial cells have a natural defense system: they identify invading viruses and chop up their DNA. Researchers decided to learn how bacteria do that. So now, the race is on to figure out how to snip out specific genes from DNA.
CRISPR stands for clustered, regularly interspaced, short palindromic repeats. They’re specific patterns of DNA sequences, which can be edited out of genes. Cas9 is a type of modified protein that’s injected into a body to work on the DNA. Think of Cas9 as the scissors that snip the DNA.
Endless supply of donor organs
Another possible CRISPR-Cas9 benefit involves pigs and human organ transplants.
What if scientists could edit pig genes to create livers, kidneys and other organs that could safely be transplanted into humans? Theoretically, CRISPR-Cas9 could manipulate the pig genes so human bodies wouldn’t reject them.
Suddenly there would be no shortage of available donor organs.
Result: Old or damaged human organs could easily be replaced, reports The Economist. If successful, the new organ supply would save lives. Currently in the U.S., an average of 22 people die each day waiting for organ transplants because of donor shortages, according to federal stats.
What’s happening now
Robust CRISPR research is ongoing. Last month, Chinese scientists said they were the first to use CRISPR to produce customized dogs. They reportedly manipulated genes called myostatins and ended up with beagles that were more muscular than regular beagles.
Myostatin genes produce proteins that inhibit muscles. In fact, you can see the effects of not having myostatins in the whippet dog breed. Many whippets have a naturally occurring mutation that lacks myostatin genes, making them grow into muscle-bound dogs.
In April, other researchers in China reported editing genes in nonviable human embryos. They were trying to correct defective genes that cause a blood disease called beta thalassemia.
Targeting ‘the obesity gene’ and Alzheimer’s
Can CRISPR help humans avoid obesity? At Harvard and MIT, researchers suspect CRISPR may be able to manipulate the so-called “obesity gene” which is thought to contribute to obesity in some humans. Remember, obesity costs society a lot of money. It is projected to rack up $344 billion in U.S. health care costs by 2018.
What about Alzheimer’s disease? Caring for Alzheimer’s patients in the United States in 2015 will cost society $226 billion, according to the Alzheimer’s Association.
Dr. Bence Gyorgy, a research fellow at Massachusetts General Hospital, told CNN in August that he and collaborators Casey Maguire and Xandra Breakefield are experimenting with lab mice to develop CRISPR-based approaches to treat Alzheimer’s and to correct a genetic form of deafness.
Initially, CRISPR appears to be better suited for destroying “bad” versions of genes that cause disease, Gyorgy said. But eventually the technique may also be able to replace those bad gene versions with normal, healthy copies.
The potential of CRISPR-Cas9 also raises huge ethical questions among scientists, doctors and bioethicists. Some fear it will open the door to exploitation of human embryos manipulated for nontherapeutic reasons. For example, parents might want to use CRISPR-Cas9 to create a child with specific attributes – like eye color or athletic characteristics. Another concern is that the technique could create unintended mutations, such as new diseases.
So, realistically, how soon could CRISPR move from laboratories to patients? In the U.S., if research progresses, human testing would still be years away, reports Forbes. But if its promise pans out, and science learns how to master it, there’s no doubt that life in the modern world will change dramatically.
Journalist Carina Storrs contributed to this report.