Could CRISPR Help Parents of Sick Children Conceive Savior Siblings?

In 2018, He Jiankui, PhD, stirred controversy when he modified the DNA of twin embryos using CRISPR to mitigate HIV risk. Now, investigators are exploring the possibilities of editing an embryo’s genes to “cure” another person who is already alive.

Although the technology is not yet precise enough, in the future it might serve as an alternative application for couples hoping to conceive a savior sibling, or a child who can serve as a donor to a brother or sister with a genetic illness.

“Families are driven to go to great lengths to seek technology that will address the health needs of even a single child with an ultra-rare disease,” said George Daley, MD, PhD, dean of Harvard Medical School.

According to a story in STAT, a California couple with a 2½ year old daughter with Fanconi anemia (FA) –a disease that can be cured with a hematopoietic stem cell transplant from a sibling – is trying to conceive another child through IVF who could act as a donor source for their daughter. To avoid having a second baby with FA, they must screen each embryo through a process called pre-implantation genetic diagnosis (PGD). The couple hopes to transfer an embryo without the disease-causing mutations, which would be edited through the CRISPR technique, and one with the same HLA complex as their firstborn to be a suitable hematopoietic cell donor. The odds that an embryo would meet these criteria are less than three in 16, so the process could take several cycles of IVF, and there are no guarantees that an embryo will successfully implant and produce a child.

“Coupling gene editing with PGD would be a way forward of making this a much more efficient and somewhat less toxic approach,” said Dr. Daley.

Source: STAT, September 16, 2019.