Reproductive medicine from the future: mitochondrial replacement techniques – IVF Arizona

The field of reproductive medicine is advancing quickly, and new technologies are becoming available that can have a dramatic impact on a couple’s chances of having a healthy baby. At Reproductive Health Center of Tucson, we’re excited about these future possibilities, and we know that many patients are too. One exciting new technology currently under development is mitochondrial replacement, and it could soon help mothers with certain genetic diseases to bear healthy offspring.

What are mitochondria? – IVF Arizona

To understand how this technique works, a little background is helpful. Inside of each of your body’s cells, there are several types of smaller structures that allow the cell to live and function. One of the most important of these is the mitochondria (my-toe-KON-dree-ah). These are the cell’s energy powerhouses, creating the energy that everything else inside the cell uses to work. Without well-functioning mitochondria, a cell can’t get much of anything done.

Two types of DNA – IVF Arizona

Most people know that DNA carries the information that creates the structures of your body. DNA is located in the nucleus (the “command center”) of the cell. Half is contributed by the mother, and half by the father, making the child a mix of the two parents. This nuclear DNA is the DNA most of us are familiar with. But it’s actually not the only DNA you have.

The really interesting thing is that mitochondria have their own DNA. Rather than being created through the nuclear DNA (like most of the structures of the cell), the mitochondria actually divide on their own, inside of your own cells, and they have their own genetic code that’s separate from the main one in the nucleus. When your own cells divide, each one takes some of the mitochondria with it.

All of your mitochondrial DNA comes from your mother. This is because the sperm is just a little packet of nuclear DNA designed for transfer, while the egg is a large and functional cell with all of the parts that a cell normally has – including the mitochondria. Your father gave you half of your nuclear DNA through his sperm, but your mother gave you the other half of your nuclear DNA as well as all of your mitochondrial DNA through her egg.

Curing mitochondrial diseases – IVF Arizona

When there’s a problem with the mitochondria, major diseases can result. Many body systems can be affected, especially the ones that use the most energy (such as the nervous system). Unfortunately, with current technology, if a mother is carrying a mitochondrial disease, she won’t be able to use her own eggs for IVF. If she does, she’ll pass on the defective mitochondria to her baby. Even if there’s nothing wrong with her nuclear DNA, there’s no way she can have a child that’s genetically related to her, because she’ll need to use donor eggs to avoid the mitochondrial issue.

That’s where mitochondrial replacement technology comes in. Using this technique, scientists can remove the diseased mitochondria from a woman’s egg, and replace them with healthy mitochondria from another woman. The nuclear DNA in the egg still comes from the original woman, so she’ll still be the genetic mother of the child.

Why is this called the “three-parent technique” of IVF?

When the treated egg is used in IVF, the child will actually have three genetic parents. The genetic father will be the man whose sperm fertilizes the egg. One genetic mother will be the woman from whom the egg was harvested, whose nuclear DNA is in the egg. (Usually, this woman would also carry the pregnancy, although a surrogate could potentially be used.) The woman who donated the mitochondria that were transferred into the egg will be a third genetic parent of the child. Although none of the donor’s nuclear DNA will be part of the child, the mitochondrial DNA will all come from that donor.

Because most of our appearance and personality characteristics are determined by our nuclear DNA, this child will be most like the father and mother whose nuclear DNA they have. However, at a cellular level, the “mitochondrial mother” will play an important role, ensuring that every cell has the energy it needs to function properly.

Why is this technique controversial?

Remember that we get all of our mitochondria from our mothers. A woman will pass on her mitochondria to her babies of both genders. When mitochondrial replacement is performed, then if the resulting baby is a girl, the new mitochondria will be passed on to all of her children. That means this technique can potentially affect many generations, so scientists are cautious about it.

However, the National Academies of Science, Engineering, and Medicine have recently released a statement in favor of the technique. They recommended that it first be performed only on male embryos, because they won’t pass on the new mitochondria to any future generations. If it goes well, then female embryos could also be used in the future.

Can you access this technique now?

For now, mitochondrial replacement is still experimental. However, it could allow women carrying mitochondrial disorders to bear their own genetic children (albeit with a second genetic mother). This would be a huge advancement for these women, who otherwise have no chance of being genetically related to their babies.

At Reproductive Health Center of Tucson, we’re excited about this and other technologies in the field of reproductive medicine. We stay up-to-date with the latest advancements, so we can bring you the very best of what the field has to offer. If you’re considering IVF in Arizona, or other types of infertility treatment, we’re a national Center of Excellence in the field and would love to help you. Learn more, or contact us to schedule an appointment.