British scientists have created human embryos with three parents
in a development they hope could lead to effective treatments for a
range of serious hereditary diseases within five years.
Researchers from Newcastle University, in northern England,
presented their findings at a medical conference at the weekend, a
university spokeswoman said.
The IVF, or test-tube, embryos were created using DNA from one man
and two women.
The idea is to prevent women with faults in their mitochrondial DNA
passing diseases on to their children.
Around one in 5,000 children suffer from mitochondrial diseases,
which can include fatal liver, heart and brain disorders, deafness,
muscular problems and forms of epilepsy.
If all goes well, researchers believe they may be able to start
offering the technique as a treatment in three to five years.
Mitochondria are tiny power packs inside cells that provide their
energy.
Faulty genetics can mean mitochondria do not completely burn
food and oxygen, leading to the build-up of poisons responsible for
more than 40 different diseases.
The Newcastle team believe these diseases could be avoided if
embryos at risk were given an effective mitochondrial
transplant.
The process involves in vitro fertilisation (IVF) and the subsequent removal of the egg's nucleus.
The nucleus is then placed into a donor egg whose DNA has been
removed.
The resulting foetus inherits nuclear DNA, or genes, from both
parents but mitochondrial DNA from a third party.
"The idea is simply to swap the bad diseased mitochondria - give a
transplant, if you like - for good healthy ones from a donor,"
Patrick Chinnery, a member of the Newcastle team, said in a
telephone interview.
"We're trying to prevent kids being born with fatal diseases."
Mitrochondrial DNA is passed down only through the female
line.
The technique has so far been tried only in the laboratory, using
abnormal embryos left over from IVF therapy, and the handful of
three-parent embryos created were destroyed after six days.
Stiff opposition to the technique is likely from critics of embryo
research who fear the creation of designer babies.
The research was presented to the Medical Research Council Centre
for Neuromuscular Diseases conference in London on February
1-2.
