Human Embryo Experiment Makes 3-Parent IVF Safer, Sets Stage for Human Trials

The road to making three-parent IVF is bumpy but shows progress. Recently, a new study shows the amount of risk couples face when embarking on this controversial process of conception.

Three-parent IVF is a process proposed to eliminate diseases that are passed on to babies via their mother's mitochondrial DNA. LA Times notes that mitochondrial DNA is a set of 37 genes that control and provide energy to cells. If a baby receives an unhealthy mitochondrial DNA, these could lead to various debilitating diseases such as MELAS and Leigh syndrome. Currently, about 778 babies in the US are born with diseases from faulty mitochondrial DNA, which have no cure and are often fatal.

During three-parent IVF, the nuclear DNA from the eggs of a healthy donor will be removed and replaced with that of the mother, resulting to a combined egg from two parents. It will then be fertilized through in vitro fertilization, where a sperm fertilizes the combined egg in a dish and incubated for a few days in the lab.

But during this process, sometimes, traces of the would-be mother's defective mitochondrial DNA are not completely removed. The study, published in the journal Nature, involved four women who has faulty mitochondrial DNA and pathogenic mutations.They also used obtained eggs from 11 women who have no history of any mitochondrial mutations.

"We wanted to understand how effectively we could get eggs from a woman carrying mtDNA mutations, their quality, and how efficiently we could transfer the nuclear DNA into a donor egg with minimal mutant mtDNA carry-over," Shoukhrat Mitalipov of the Oregon Health & Science University told The Scientist.

Results show that 75 percent of the fertilized eggs reached the blastocyst stage in five days and out of the 22 fertilized eggs, 99 percent of those were from the donors. The eggs, though not implanted for pregnancy, gives a possibility for human trials, The Washington Post reports.

However, the researches note that some of the mutant DNA still remained in the fertilized eggs, which led to the scientist's conclusion that to solve this problem, fertility specialists should filter and match parents with compatible egg donors.