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We Can Cure Disease by Editing a Person’s DNA. Why Aren’t We?

Fyodor Urnov (NY Times)

December 9, 2022

The parents of a 2-year-old girl write that their daughter “could die within the next year” because a genetic mutation is causing her heart to fail.

“Time is quickly running out for me,” writes a man in his mid-30s whose DNA harbors a genetic mistake certain to destroy his brain within a matter of years.

“Watching my sons disintegrate before my eyes is heartbreaking,” writes a mother with two children affected by a faulty gene that affects cognition, speech and mobility. One of her sons, she writes, is still walking and in college, but “it is only a matter of time before he will be in a wheelchair and his cognition will decline.”

Stories of human tragedies like these arrive in my inbox with increasing, painful regularity. People write to see if I can build a medication to fix their genes and stave off an early, imminent death. Their wish is not futuristic: Many scientists, including me, build DNA fixes for a living.

Over the past decade, thousands of people have agreed to be genetically engineered in experimental trials to develop these treatments — and to save their lives. Famously proposed 50 years ago, such fixes, or gene therapies, began earnest development in 1989. After fits and starts, the first real cures for children born with no functioning immune system arrived in the early 2000s.

Daniel Forero

Several approved gene therapy medicines now exist. All involve taking a virus, replacing its harmful contents with a disease-treating gene, and injecting it into a person (or exposing the person’s cells to that virus in a dish and putting them back). Though effective, these treatments remain cumbersome to build and jaw-droppingly expensive: One recently approved gene therapy for people with an inherited bleeding disorder costs a record-breaking $3.5 million for a single-use vial, making it the most expensive drug in the world.

Gene editing is much newer technology and builds on the gains of gene therapy. Instead of using a virus, however, gene editing relies on a molecular machine called CRISPR, which can be instructed to repair a mutation in a gene in nearly any organism, right where that “typo” occurs. Impressively versatile, potential applications for CRISPR range from basic science to agriculture and climate change. In medicine, CRISPR gene editing allows physicians to directly fix typos in the patients’ DNA. And so much substantive progress has been made in the field of genetic medicine that it’s clear scientists have now delivered on a remarkable dream: word-processor-like control over DNA.

The first person to be gene-edited with CRISPR was treated only three years ago for a disorder of red blood cell production, and since then, the technology has been used to treat congenital blindness, sickle cell disease, heart disease, nerve disease, cancer and H.I.V. While not all diseases have a single-gene basis, most have a genetic component. Early studies suggest that conditions like heart disease, chronic pain and Alzheimer’s disease could all be treated with CRISPR. Dr. Jennifer Doudna, a winner of the 2020 Nobel Prize in Chemistry for CRISPR gene editing along with Dr. Emmanuelle Charpentier, aptly described it as a “profound opportunity to change health care for many people.”

Urnov, F. (2022, December 9). We can cure disease by editing a person’s DNA. why aren’t we? The New York Times.



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