CLICK ON weeks 0 - 40 and follow along every 2 weeks of fetal development
Genetically modified baby boy - with 3 parents
On September of 2015, The Francis Crick Institute in London announced they would apply to edit human DNA in embryos, this was followed by the August 4, 2016 announcement by the National Institutes of Health Office of Science Policy that United States scientists may now edit DNA in human embryos and adults, using the CRISPR technique.
Appearing in the magazine Society for Reproductive Endocrinology and Infertility, which broke the story, a smiling Dr. John Zhang, fertility specialist at New Hope Fertility Center, New York City, presents the newborn he helped into the world.
mtDNA, or mitochondria DNA, converts food energy (calories) into a form that cells use to divide, grow into tissues and form organs — its loss or failure deprives cells energy for continued development. Mitochondrial DNA is passed from mothers to sons and daughters only through the female egg, so sons cannot pass mtDNA mutations along to their children. If mom carries a mtDNA mutation, her newborn faces a number of life-threatening conditions.
Zhang used an tchnique called spindle nuclear transfer, SNT, to create five human embryos. He removed the nucleus from each of the eggs collected from the mother — the bulk of all human DNA is in the cell nucleus. Each of mom's nuclei were then inserted into a donor egg stripped of its original nucleus, but containing healthy mitochondria without mutations — from a donor.
Only one of the embryos created for this couple had a normal number of chromosomes result after fertilzation. That one was transferred into mom.
The regulatory situation in the United States “kind of doesn’t make any sense,” Gleicher argues:“because what it results in is exactly what you have been witnessing”—essentially, an experiment that moves “to places with no supervision.”
Dieter Egli PhD, stem cell biologist at Columbia University, agrees. “For me, the lesson here is that it’s very important that regulatory agencies like the FDA move forward,” he said. “This could have been done in the United States by groups that have many years and decades of research [experience].”
Clinical embryologist Jacques Cohen of Reprogenetics in Livingston, New Jersey, who has previously advised Zhang’s team about regulatory issues, defends the decision :“Just because this was done in Mexico doesn’t mean it was not done ethically,” says Cohen, who himself led controversial fertility experiments in the 1990s involving the transfer of cytoplasm, in which the resulting babies also had three genetic parents.
Zhang is not new to embryo modification. In China in 2003, he swapped a nucleus from one egg to another, though the egg was already fertilized. Reported in The New York Times, the research appeared only last month, in Reproductive BioMedicine Online. The 30-year-old woman who became pregnant, lost her twins before birth.
In 2009, Shoukhrat Mitalipov PhD, of the Oregon Health & Science University in Portland achieved similar success in macaque monkeys. Like others, Mitalipov said in a statement to Science that it was troubling that “desperate parents” were being forced to “countries with less oversight.” He attributes the failure to congress for blocking the FDA from allowing mitochondrial replacement to be attempted.
Abstract "Pregnancy derived from human zygote pronuclear transfer in a patient who had arrested embryos after IVF"
Nuclear transfer of an oocyte into the cytoplasm of another enucleated oocyte has shown that embryogenesis and implantation are influenced by cytoplasmic factors. We report a case of a 30-year-old nulligravida woman who had two failed IVF cycles characterized by all her embryos arresting at the two-cell stage and ultimately had pronuclear transfer using donor oocytes. After her third IVF cycle, eight out of 12 patient oocytes and 12 out of 15 donor oocytes were fertilized. The patient's pronuclei were transferred subzonally into an enucleated donor cytoplasm resulting in seven reconstructed zygotes. Five viable reconstructed embryos were transferred into the patient's uterus resulting in a triplet pregnancy with fetal heartbeats, normal karyotypes and nuclear genetic fingerprinting matching the mother's genetic fingerprinting. Fetal mitochondrial DNA profiles were identical to those from donor cytoplasm with no detection of patient's mitochondrial DNA. This report suggests that a potentially viable pregnancy with normal karyotype can be achieved through pronuclear transfer. Ongoing work to establish the efficacy and safety of pronuclear transfer will result in its use as an aid for human reproduction.
John Zhang MD, of New Hope Fertility Center in New York City, holding newborn boy
whose faced is blurred for his and his family's privacy.
Image Credit: Public Domain