British researchers gave the green light to the fertility method allowing three parents to have a single baby, making the UK the first country in allowing such procedures.
Although health risks were noted for the ‘careful’ adoption of the fertilization method, it was still approved for implementation in the following months.
The procedure has been endorsed by the Human Fertilization and Embryology Authority (HFEA), allowing mothers to circumvent passing down mitochondrial diseases to their babies.
So far, there is no cure or treatment for any of the mitochondrial diseases other than modifying an embryo’s structure.
It’s just the mitochondria
Mitochondria is found within cells, being a cellular structure with the task of producing energy. Mothers pass the mitochondria to their babies, and a mutation of the genes found in the mitochondria is the source of lethal mitochondrial diseases that affect the child’s brain and muscles. Even if the mother does not display any symptoms, it is possible that she passes down the disease to her children, forcing her to miscarry.
The term “three-parent baby” has been coined as erroneous but nonetheless it has stuck even if the mitochondria does not have anything to do with a person’s traits, so the individual who donated the mitochondria for the procedure cannot be categorized as a parent.
According to HFEA, mitochondrial diseases affect at least one person out of every 10,000, adding up to 3,500 women in the United Kingdom. This type of illness has been categorized as slowly deteriorating and painful to watch, as it can claim a child’s life in a few years, depleting the body’s structures that need energy to function until they collapse.
“Watching your child die, knowing there’s no cure and nothing you can do, it’s cruel, and knowing you carry the gene that will more than likely be passed on to other future children, it’s a double blow,” stated Liz Curtis of the Lily Foundation to BuzzFeed News.
Mitochondria is responsible for the vast majority of the energy that our body uses to sustain itself. The most energy-demanding structures are the brain, heart, lungs, and muscles, all of which become deteriorated if the person is diagnosed with a mitochondrial disease. Symptoms also include strokes, seizures, inability to talk and walk, and many other ailments. Although this type of illness primarily affects children, adults can live long enough to see themselves affected by such condition.
How does a baby have two mothers?
Initially, researchers discovered that cytoplasm, the fluid containing the mitochondria and other cellular structures, was the main contributor allowing an in vitro fertilization procedure to be successful. Since 1996, this procedure has repeatedly been performed, and the child has grown with the donor’s mitochondria inside of them.
This technique named “pronuclear transfer” has the mother’s egg and the donor’s egg fertilized at the same time. As both eggs become zygotes, the pronuclei of the mother’s egg would be inserted into the donor’s egg, while the donor’s pronuclei would be discarded. In essence, the mother’s baby would grow inside the donor’s egg.
Even if the procedure is perceived as safe and relatively straightforward, people have protested against it because it theoretically destroys two embryos, which in terms of pro-life activists translates to two babies. There’s also the risk that the mitochondria carry over to the donor’s egg, which would become infected with the mitochondrial disease.
The technique has been improved with time, making it, so the amount of mistakenly transferred mitochondria were reduced to a 2 percent, but it seems that the disease can originate from even 1 percent of mutated mitochondria.
A more advanced method was developed early in April, where the mother’s egg’s chromosomes are transferred to the donor’s, thanks to the fact that they attach to a series of protein fibers called spindles. After the chromosomes are inserted into the donor’s egg, the cell is then fertilized and transferred to the mother’s uterus to allow the baby to develop normally. Spindle transfer was shown to be more secure than pronuclear transfer, but there’s the risk that chromosomes may fall off the protein fibers, which could cause chromosomal diseases such as Down’s syndrome, infertility, muscular dystrophy, Cri du chat syndrome and more.
Even if the treatment’s objective is to allow the baby to grow without mitochondrial diseases, opponents claim that enabling the procedure to take place opens up the pathway to designer babies, where eventually parents will be able to genetically modify their child before it is born.
This claim is far-fetched but not completely misguided. At first, abortion was mostly ruled illegal, with the sole exception of when the baby would put the mother at risk of dying during childbirth. With time, restrictions have been lifted, and abortion is now legal in Washington state and New York, while in states such as Florida, California, and New Mexico, it is legal in cases of danger to the mother’s health, rape, damaged fetus, or incest.
The HFEA will be meeting on December 15 to make a decision based on the parliamentary vote that ruled the mitochondrial replacement technique legal.