gene therapy


Why We Need To Talk Now About The Brave New World Of Editing Genes

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(Image: NIH)

It was standing room only in the Harvard Medical School auditorium last week, the atmosphere electric as an audience of hundreds hummed with anticipation — for a highly technical talk by a visiting scientist, Dr. Jennifer Doudna of Berkeley. Near the front sat the medical school’s dean, Dr. Jeffrey Flier.

Dr. Jennifer Doudna (Vimeo screenshot)

Dr. Jennifer Doudna (Vimeo screenshot)

“I don’t believe in my years at Harvard Medical School I’ve ever seen a crowd of this magnitude for a lecture of this kind,” he said.

The draw?

“The draw is, this is one of the most exciting topics in the scene of biology today.”

That buzzworthy biology topic is a revolutionary new method to “edit” DNA that has spread to thousands of labs around the world just in the last couple of years.

Suddenly, it’s no longer purely science fiction that humankind will have the ability to tinker with its own gene pool. But should it?

Learn This Acronym: CRISPR

The hot new gene-editing tool is known by the acronym CRISPR, for “clustered regularly interspaced palindromic repeats.” It acts as a sort of molecular scissors that can be easily targeted to cut and modify specific genes.

(Source: NIH)

(Source: NIH)

CRISPR occurs naturally in bacteria, but scientists are now learning to harness its power to alter DNA for research across the board — cancer, HIV, brain disease — even to make better potatoes. Just this week, the journal Science published a paper on possibly using CRISPR to try to stop female mosquitoes from spreading deadly diseases.

CRISPR looks particularly promising for human diseases that hinge on just one gene, like sickle-cell anemia or cystic fibrosis. Someday, the hope is, CRISPR and gene-editing tools like it will let us cure what are now lifelong diseases by simply deleting and replacing a baby’s “broken” gene. Continue reading

Imagining Gene Therapy For Girls With Rare Rett Syndrome

By Karen Weintraub
Guest Contributor

Imagine your daughter has a debilitating genetic disease — a disorder that will plague her for the rest of her life. Now imagine hearing about a treatment that might improve her condition dramatically.



That the kind of brimming-with-hope feeling many parents had six years ago when Scottish researcher Adrian Bird announced that he had reversed a genetic condition called Rett Syndrome in adult mice.

Of course everyone who heard about the study understood that curing a mouse is not the same as helping a person, but the improvements stunned researchers who had assumed that a mouse would never be able to recover from the restricted mobility, tremors and unusual brain activity that characterize the mouse version of the disease.

The parents of girls with Rett Syndrome – which occurs mainly in females, because males with the genetic mutation usually die before birth – suddenly had hope that their children might someday be able to talk, run, wave or blow them a kiss. Continue reading

First Human Gene Therapy Trial Planned For Deadly Tay-Sachs Disease

A child who died of Tay-Sachs Disease

Imagine you have an adorable baby who’s oddly slow to start sitting up. You get the child tested and to your horror, the verdict is a genetic death sentence: Tay-Sachs Disease. Exceedingly rare, but inexorably fatal. You now know that your baby likely won’t live to kindergarten age, and instead of growing up will slide down into blindness, seizures, paralysis. No cure. No hope.

That is how Tay-Sachs Disease has tended to unfold, since it was first described in the late 19th century. But now, for the first time, scientists say, there is a chance — though it is far from certain — that in the foreseeable future, that merciless course could be altered.

If all goes as planned, in the second half of next year researchers from the University of Massachusetts Medical School, Massachusetts General Hospital and elsewhere will launch a clinical trial of a new gene therapy treatment in up to 12 children with Tay-Sachs Disease.

The treatment involves infusing, deep into the brain, engineered viruses that can effectively turn cells in the brain into “micro-factories” of the enzyme that is so lethally absent in people with the disease. Cats with a feline version of Tay-Sachs normally die by about age four months. The gene therapy treatment has kept them going strong beyond 18 months.

A cat with an untreated feline version of Tay-Sachs Disease

“This is the first time there’s a real prospect for a possible treatment for Tay-Sachs and similar genetic diseases that affect the brain,” said Susan Kahn, executive director of the National Tay-Sachs & Allied Diseases Association (NTSAD), a driving force behind the research along with other family foundations. “Parents who had affected children as far back as the 1950s are saying, ‘Wow, I never thought I would see this day.'”

Now for the inevitable cautions, from UMass researcher Miguel Sena-Esteves:

“Usually, in my first breath, I tell people about the great results we’re observing in the cats,” he said. “In the second breath, I tell them there’s absolutely no guarantee that because we’re getting these results in animals, we’ll see the same in a human. We know from experiments in many, many fields that what works in another species doesn’t necessarily work in a human. If it did, we would have cured cancer by now.”

Also, gene therapy, in particular, has a past marked by some major disappointments. Touted as a potential cure for just about anything in the 1990s, it all but crashed after an 18-year-old patient died of a massive immune reaction in 1999 and it turned out that the viruses used as “vectors” to carry the genes sometimes induced leukemia.

Lately, however, gene therapy has begun to rack up successes, said Dr. Terence Flotte, dean of the UMass School of Medicine and himself a gene therapy researcher. It helped restore some vision in blind people with a rare genetic disease of the retina, he noted, and seems to show particular promise for diseases of the brain and central nervous system.

Continue reading