One in every 5,000 children are born with a genetic mutation, and scientists are now looking into birthing babies with three parents to help prevent diseases caused by mitochondrial mutations.
Most recently, researchers led by Douglass Turnbull at Newcastle University used a three-person in vitro fertilization to help prevent babies from inheriting mitochondrial mutations from a parent. The process involves effectively transferring genetic material from the egg of a woman with a mutation into the egg of a healthy woman, which is then fertilized by male sperm. This process provides the baby with DNA from all three parents, and a mutation-free birth.
Turnbull, a neurologist who has treated plenty of children with fatal disorders, became motivated to work on this project after treating a family who had lost several children due to genetic diseases. He thought, “whatever we do, we’re never going to be able to help families like that,” he told Nature. But Turnbull turned to assisted-reproduction techniques to begin exploring how such genetic mutations could be prevented. Turnbull began focusing specifically on the mitochondria, the cell’s power houses, and how genetic mutations occurred in them.
Nature describes the potential clinical process:
First, a fertilized egg cell is zapped with a laser, making a hole in its membrane. Then the embryologist eases a pipette into the hole and plucks out the pronuclei, twin genetic structures that result from fertilization. Next, the researcher empties a fertilized donor egg of its genetic material and squirts the pronuclei into the hollow egg. The feat takes several minutes (see video). If the United Kingdom approves clinical use of the procedure, the egg would then be incubated for a few days until it develops into a blastocyst of between 50 and 200 cells, which would then be transplanted into a woman's uterus.
So far, trials have been completed in monkeys, mice, and human cells in culture. Before clinical trials in humans can begin, however, the UK Parliament must first vote on it. And though the research has proven to be successful so far, plenty of scientists argue against it, noting that the procedure might be unsafe, not entirely vetted or vigorously tested, and still remains an unknown and misunderstood frontier. Several bioethicists, meanwhile, are worried that the procedure “would open the door to further genetic alterations of human beings with unforeseeable consequences.”
But Turnbull argues that three-way IVF isn’t the same thing as producing designer babies. “This is about preventing serious, life-threatening, disabling diseases,” he told Nature.