The Rarest of All Diseases Are Becoming Treatable
This year, gene-editing technology was customized to fix mutations in a single patient’s genes for the first time.
For a decade after its discovery, CRISPR gene editing was stuck on the cusp of transforming medicine. Then, in 2023, scientists started using it on sickle-cell disease, and Victoria Gray, a patient who lived with constant pain—like lightning inside her body, she has said—got the first-ever FDA-approved CRISPR gene-editing treatment. Her symptoms vanished; so did virtually everyone else’s in the clinical trial she was a part of.
This year, the technology has started to press beyond its next barrier. Most of the 8 million people globally who have sickle-cell disease share the same genetic mutation; treating rare disorders will require dealing with many different mutations, even within the same disease. And although rare diseases affect 30 million Americans in total, relatively few people are diagnosed with each one. Fyodor Urnov, the scientific director of UC Berkeley’s Innovative Genomics Institute (IGI), showed me a list of rare diseases and pointed to one carried by only 50 people. “Who’s going to work on a disease with 50 patients?” he asked. And even within one disorder, each person might need their own customized CRISPR treatment. Drug developers have little financial incentive to spend years and millions of dollars designing therapies that may need to be tailored to literally one person…
…“We have been moving in the direction of thinking about CRISPR as a platform for some years,” Jennifer Doudna, the IGI’s founder, who shares the Nobel Prize for discovering CRISPR gene editing, told me. But, in her mind, 2025 was the first time many people understood its potential. A baby named KJ Muldoon is a big reason why.
