There’s been a first in the use of in vitro fertilization (IVF) to help parents avoid passing on a fatal rare disease to their baby.
In what many medical experts are calling a “revolutionary” medical event, a baby with DNA from three donors has been born.
As first reported in New Scientist, a science and technology magazine published in the U.K., the baby boy was born on April 6, 2016 and doctors say he appears healthy. His parents were treated by U.S. fertility specialists in Mexico, where there are no laws prohibiting such methods. His mother carries a genetic mutation for Leigh syndrome, a rare neurological disorder that usually becomes apparent in the first year of life and is generally fatal.
The newborn’s mother had suffered four miscarriages and had two children who died from Leigh syndrome, one at age six and one at eight months. It’s a devastating disease for parents and children. Symptoms of Leigh disease usually progress rapidly and lead to generalized weakness, a lack of muscle tone and a buildup of lactic acid in the body, which can cause respiratory and kidney problems. Children rarely live more than six or seven years.
While the mother herself is healthy, a gene for the disease resides in her DNA, in the mitochondria that powers cells. In this mother’s case, about 25 percent of her mitochondria reportedly carries the disease-causing mutation.
In order to avoid transferring the disease, the couple sought help from Dr. John Zhang, a reproductive endocrinologist at New Hope Fertility Center in New York City.
“This mitochondrial disease is usually a very devastating situation for the babies and the family,” Zhang told CBS News.
The controversial procedure involved using the three-parent IVF technique to ensure that the disease mutation would not be passed along to the baby. So far, it seems to have worked.
The procedure, called spindle nuclear transfer, involves removing the healthy nucleus from one of the mother’s eggs and transferring it to a donor-egg, which had, had its nucleus removed. The resulting egg – with nuclear DNA from the mother and mitochondrial DNA from a donor – was then fertilized with the father’s sperm.
The resulting embryo contained genetic material from three parents – the mother, the egg donor, and the father.
According to New Scientist, the scientists in this case created five embryos using the technique. Only one developed normally and that embryo was implanted in the mother.
The baby has not shown any signs of developing the illness, Zhang said. His mitochondria have been tested and less than one percent carries the mutation, believed to be too low a level to lead to disease.
The controversial fertility method is not legal in the United States. Zhang told New Scientist that they conducted the procedure in Mexico because “there are no rules” there.
The procedure received widespread media attention when lawmakers in the U.K. became the first to approve its use last year.
Sian Harding, a medical professor and bioethics adviser who reviewed the ethics of the technique in the U.K., told New Scientist the case seems to have been handled according to ethical standards.
“It’s as good as or better than what we’ll do in the U.K.,” said Harding.
Much of the controversy surrounding this procedure involves safety and religious concerns.
Harding notes that this is not the first time multiple DNA has been used to try and create a healthy baby. “Last time embryologists tried to create a baby using DNA from three people was in the 1990s, when they injected mitochondrial DNA from a donor into another woman’s egg, along with sperm from her partner. Some of the babies went on to develop genetic disorders, and the technique was banned. The problem may have arisen from the babies having mitochondria from two sources.”
In Britain, where the procedure allowing DNA from three parents was approved in February 2015, leaders disagreed heatedly on the issue while it was up for debate in the House of Commons, with some raising concerns about “designer babies” and “playing God.” Leading churches in Britain – both Protestant and Catholic – opposed the procedure on religious and ethical grounds.
Medical and moral concerns about this IVF method are most likely going to continue as experts look for ways to refine the controversial procedure.
But for one couple, being able to cradle their newborn - that shows no sign of carrying the deadly Leigh disease - will forever be a precious gift.
Story source: Mary Brophy Marcus, http://www.cbsnews.com/news/first-3-parent-dna-baby-born-rare-disease/