Even then, patients will not receive the treatments if insurers and governments refuse to pay. It is a real risk. For example, a different gene therapy for beta-thalassemia, developed by Bluebird Bio, was withdrawn from the European market after governments refused to pay the $1.8 million price tag.

CRISPR 2.0

The first generation of CRISPR treatments is also limited in another way. Most use the tool to damage DNA, essentially turning off genes, a process described as “genomic vandalism” by Harvard biologist George Church.

Treatments that attempt to break genes include one designed to try to eliminate HIV. Another is the one Gray got. By breaking a specific piece of DNA, his treatment unlocks a second version of the hemoglobin gene that people normally use only as babies. Since hemoglobin is the errant protein in sickle cell disease, starting another copy solves the problem.

According to Liu’s analysis, two-thirds of current studies aim to “disrupt” genes in this way.

Liu’s lab is working on next-generation gene-editing approaches. These tools also use the CRISPR protein, but it’s designed not to cut the DNA helix, but instead to cleverly swap individual genetic letters or make larger edits. These are known as “base editors”.

According to Lluís Montoliu, a genetic scientist at Spain’s National Center for Biotechnology, these new versions of CRISPR have “lower risk and better performance”, although it remains difficult to send them “to the correct target cell in the body”.

In his lab, Montoliu uses basic editors to cure albinism in mice, in some cases from birth. It’s a step, she says, toward a treatment newborn humans could receive, though not to change their skin color. Instead, she dreams of putting Liu’s molecules in her eyes to correct the severe vision problems that albinism can cause.

However, so far, the albinism project is not a commercial venture. And that points to one of the biggest limits on the impact of CRISPR now and for the foreseeable future. Almost all of the ongoing CRISPR trials are targeting cancer or sickle cell disease, and several companies are chasing exactly the same problems.