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 During two days of public hearings starting on
Tuesday, scientists were scheduled to present their research to
outside advisers to the U.S. Food and Drug Administration. The
agency will decide whether safety concerns raised by three-parent
IVF are minimal enough to allow clinical trials to begin.
The committee is focusing only on the science, and at the end of
Tuesday's hearing some committee members expressed concern that
animal research cannot yet show that human studies would be safe for
women and any children born via the three-parent technique.
Several panelists felt "there was probably not enough data in
animals . . . to move on to human trials without answering a few
additional questions" about safety, said committee chairman Dr. Evan
Snyder of the Sanford/Burnham Medical Research Institute in La
Jolla, California, in summarizing their views at the end of
Tuesday's session.
Although the panel has not been asked to consider legal or ethical
issues, members of the public focused on those. Speakers warned the
panel that use of three-parent IVF "could alter the human species,"
represented "an unprecedented level of experimentation on
non-consenting human subjects" (meaning any children born via the
technique), and "could open the door to genetically modified
children" who would be "manufactured products."
In the three-parent procedure, one man would donate sperm and all
its DNA for in-vitro fertilization. The would-be biological mother
would contribute the egg and most of its DNA. But if the mother
carries harmful genetic mutations in cellular structures called
mitochondria, scientists would remove her unhealthy mitochondria and
substitute those of a second woman so the baby would not inherit a
potentially devastating "mitochondrial disease."
Allowing such procedures "would produce genetically modified human
beings," Marcy Darnovsky, executive director of the Berkeley,
California-based Center for Genetics and Society, a non-profit that
focuses on genetic and reproductive technologies, told the
committee.
If the FDA allows clinical trials, she warned, it would introduce "a
regime of high-tech consumer eugenics" and represent "the first time
a government body had okayed genetic changes for humans and their
descendants."
Although the FDA committee is considering only scientific issues,
such as whether animal research can show mitochondrial manipulation
is safe or not, the agency said it is prepared to go beyond that.
"We have heard the concerns expressed at the advisory committee
meeting, and will take the information back to consider whether we
need to facilitate a public discussion and, if so, how best to do
this," spokeswoman Jen Rodriguez told Reuters.
PREVENTING DISEASE
Some human eggs contain mutations in little-known genes inside
mitochondria, which are structures that produce energy, fight
viruses and perform other crucial functions in all cells.
Scientists have identified about 700 mutations in mitochondrial DNA
that cause what Dr. Salvatore DiMauro of Columbia University
described to the FDA panel as "a Pandora's box of diseases,"
including recurrent strokes, seizures, blindness, deafness,
diabetes, and a brain-destroying illness called necrotizing
encephalopathy.
Mitochondrial disease cannot be diagnosed prenatally, DiMauro said.
In the United States, biologist Shoukhrat Mitalipov of Oregon Health
and Science University told the committee that up to 4,000 children
per year are born with inherited mitochondrial mutations.
Mitochondrial diseases, he added, are incurable.
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That has spurred research on how to strip out
mitochondria with genetic mutations and replace them with healthy
mitochondria.
One technique, pioneered at Newcastle University in England, starts
with a fertilized egg whose mitochondria contain mutations.
Scientists remove the embryo-to-be's genome, also called nuclear
DNA. This DNA is then injected into an egg from a second woman whose
mitochondrial DNA is healthy and whose own nuclear DNA has been
removed. Result: a fertilized egg with healthy mitochondria and its
parents' nuclear DNA. Another technique, called
maternal spindle transfer, starts with an unfertilized egg from a
woman with mitochondrial mutations, explained Oregon's Mitalipov,
who has used the technique in monkeys and said it is ready for human
trials. The egg's genome is removed and injected into a healthy egg
whose own genome has been removed. The egg, with standard DNA from
the mother-to-be and mitochondrial DNA from the egg donor, is then
fertilized with the would-be father's sperm.
Last year, British health authorities announced that they would
draft regulations for three-parent assisted reproduction. The
regulations have yet to be issued and would require the consent of
Parliament to be implemented.
Although some opponents of mitochondrial manipulation raise the
specter of genetic engineering, replacing mutation-filled
mitochondria with healthy ones would not be genetic engineering in
the usual understanding of the term. It would not make a child
smarter, more athletic, more attractive, or otherwise different from
what his genome and environment would otherwise produce.
The phrase "designer babies conjures up the wrong message," panel
member John Gearhart, a stem-cell scientist at the University of
Pennsylvania School of Medicine, said in discussing media coverage
of the issue. "That leads to a complete misunderstanding on the part
of the public of what this is all about."
The FDA has authority over any clinical trials of mitochondrial
manipulation as part of its mandate to protect human research
subjects, which in this case includes women and any children born
from the procedure.
For over a decade, the FDA has forbidden production of three-parent
embryos in humans without its explicit permission. In 2001,
researchers combined ingredients from healthy eggs with the eggs of
infertile women and fertilized the merged ova with sperm. Just over
a dozen live births resulted, but since then under the FDA ban U.S.
scientists have used the techniques only on mice, monkeys, cows and
other animals.
(Reporting by Sharon Begley; Editing by
Michele Gershberg, Andre Grenon and Ken Wills)
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