A CRISPR edit of their embryos could correct a mutation that causes hearing loss, but is the risk worth it?


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Yevgenievna and her husband have a genetic form of deafness and do not want to pass on their mutations to a child.




On a lightly snowing Sunday evening in a suburban Moscow restaurant loud with live Georgian music, a woman in her late 20s joins me to discuss her potential participation in Denis Rebrikov’s controversial plans to create gene-edited babies (see main story, p. 562). Yevgenievna—she does not want to be identified beyond her patronymic—has been deaf since birth and cannot hear the music. But she can hear some sounds with the help of a hearing aid and is adept at reading lips.

Yevgenievna and her husband, who is partially deaf, want to have a child who will not inherit hearing problems. Russia has no clear regulations prohibiting editing in vitro fertilization (IVF) embryos to create altered babies, but Yevgenievna is deeply ambivalent about the risks of the CRISPR genome editor. She is also uneasy about publicity. “We were told if we become the first couple to do this experiment we’ll become famous, and HBO already tried to reach me.”

She and her husband, who could hear until he was 15 years old, have a daughter—Yevgenievna asks me not to reveal her age—who failed a hearing test at birth. Doctors initially believed it was a temporary problem, but 1 month later, “We were told our daughter had zero hearing,” Yevgenievna says. “I was shocked, and we cried.”

Their daughter could have received a cochlear implant, which uses surgically inserted electrodes to stimulate the auditory nerve. People with such implants can understand speech, although they typically can’t hear music. But she developed partial hearing and, like her father, does well with hearing aids. And friends in the Russian deaf community had bad experiences with implants—likely because they didn’t receive the proper rehabilitation after the surgery.

Later, they learned their daughter had one of the most common genetic causes of hearing loss, a mutation called 35delG, in both copies of GJB2, a gene key to the function of ear cells. Neither parent had ever had their genes tested—or thought a child could inherit their hearing problems.

This summer, Yevgenievna decided that despite her reservations about cochlear implants, she wanted one for herself. Through the hearing specialist she found, she learned of a genetic study of deaf couples who wanted to have children. This led the couple to Rebrikov, who scanned their genomes. If either Yevgenievna or her husband had a normal copy of GJB2, a fertility clinic could have created embryos by IVF and tested a few cells in each one to select a heterozygote—which would have normal hearing. But they learned that like their daughter, they are both 35delG homozygous. “We were told the only option [to have a hearing child] would be to edit an IVF embryo,” she says.

Yevgenievna says Rebrikov explained how CRISPR editing works and some of the risks. She understands an edit might fail to correct the deafness gene in all cells of an embryo and might create unwanted, dangerous mutations. Those discussions left her “both for and against the experiment,” she says. “We were impressed by this wondrous possibility.” But then she consulted hearing specialists. “Many told me that it’s better to have a deaf child and an implant rather than a genetically modified baby.”

Yevgenievna’s husband is now willing to take the risk. “If I said yes today, he’d say, ‘Yes, let’s do it,’” she says, noting that “he greatly supports Rebrikov and his activities.” But her husband is leaving the decision to Yevgenievna, who hasn’t decided for sure she wants a second child, let alone one edited with CRISPR. “Which is better: to hear music or be suffering from cancer?”

Yevgenievna has not even agreed to the ovarian stimulation that would allow harvesting of multiple eggs, the first step in the protocol. This month, she had her own cochlear implant surgery, and emailed afterward that she and her husband often discuss “the opportunity.”

“I believe one should come to this as confidently as I decided on a cochlear implant,” she says. “It is worth noting that 2 years ago I was an ardent opponent of the cochlear implant, but when I learned more, I changed my mind, and I am happy that I decided to take this step. The same is true with Rebrikov’s experiment. Time will tell.”



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