Posted on 09/09/2005 6:05:10 AM PDT by NYer
BRITISH scientists have been given permission to create human embryos that will have three genetic parents.
The fertility watchdog cleared a team at the University of Newcastle upon Tyne yesterday to conduct an experiment to prevent genetic disease by merging single-cell embryos with donated eggs.
The decision to approve the procedure on appeal, after two previous applications were rejected, is controversial because it could eventually lead to the birth of children who carry genes from two mothers and a father.
It also opens the possibility of “germ-line” genetic engineering, because any children born would carry added genes that would be passed to successive generations.
At present, gene therapy to alter defective DNA is permitted only when such changes would not be passed on.
The licence awarded yesterday by the Human Fertilisation and Embryology Authority (HFEA) allows only experimental use of the technique and not the implantation into a womb of any resultant embryo.
The Newcastle team does not envisage applying for permission to conduct such procedures for reproductive purposes until several years of research have shown it to be effective and safe, though the ultimate goal is to employ it to create healthy children.
Some observers said the HFEA had overstepped its remit when the Government has begun a review of embryology legislation. A legal challenge is likely because the appeal turned on reinterpreting a ban on altering the genetic structure of a cell.
The researchers, led by Professor Doug Turnbull and Mary Herbert, want to prevent inherited diseases caused by mutations in the DNA in cell structures called mitochondria, which provide a cell’s energy.
About one in 5,000 people carry defects in the mitochondrial DNA. Most lead only to mild effects, but in rare cases defects can cause miscarriage, or fatal brain, liver and kidney damage in offspring. One patient the team hopes to help has had five miscarriages, and eventually gave birth to a child with profound brain damage.
Mitochondria are inherited from the mother. The team plans to replace defective mitochondria in eggs with working ones from donor eggs.
First, an egg from a woman carrying mitochondrial defects will be fertilised in vitro using her partner’s sperm. At the point of fertilisation, two “pronuclei” containing genetic material from the mother and father will be removed, and injected into an unfertilised egg from which the nucleus has been removed.
This donated egg will contain healthy mitochondria, but none of the nuclear DNA that makes up most of the human genetic code.
But mitochondria contain 37 genes, so the embryo will have been created with a genetic contribution from three individuals — the father, the mother who provided the nucleus, and the donor who provided the mitochondria.
If the embryo grows into an adult woman, she would pass on the donated mitochondria to any children of her own, raising concerns about germ-line genetic manipulation.
The procedure is not cloning, as the embryo that develops as a result will have a full complement of genes in its nucleus from a mother and a father. Clones created by nuclear transfer are genetically identical to the adult from which they are cloned, with the exception of their mitochondrial DNA.
Professor Turnbull initially applied to the HFEA for approval for these experiments last year, but was refused twice by its licence committee.
The watchdog was concerned because it is not allowed to approve changes to the genetic structure of an embryo.
The HFEA has now decided that this does not exclude changes to an embryo’s mitochondrial DNA, but prevents only alterations of the nuclear DNA, which contains most functional genes.
A spokesman for the authority said that after taking expert scientific advice, its appeal committee had been satisfied that the research was permissible under the Human Fertilisation and Embryology Act 1990, and that the experiment was “necessary and desirable” to investigate prevention of a serious disease. Professor John Burn, who heads the Newcastle Institute of Clinical Genetics where the work will be performed, said: “I am confident, after debating at length with the team, that this is within both the letter and the spirit of the law.
“It is a debateable issue and I do not want in any sense to diminish its significance, but mitochondria are not part of the genetic material that we consider in a sense makes us as human beings. All their genes do is make mitochondria, and many, many people share the same mitochondrial genomes.
“My belief is that what we are doing is changing a battery that doesn’t work for one that does. The analogy is with a camera: changing the battery won’t affect what’s on the film, and changing the mitochondria won’t affect the important DNA.”
Josephine Quintavalle, of the pressure group Comment on Reproductive Ethics, said that the ruling set a dangerous precedent. “This shows once again that the HFEA does not have any regard for public consultation and the views of the public,” she said.
Hussein Mehmet, of Imperial College, London, said that the authority had criticised similar research abroad. “The licence awarded by the HFEA appears to contradict their own point of view,” he said.
“Similar experiments carried out by an American group were frowned upon by the HFEA, although it should be stressed that those experiments were aimed at curing infertility while this research will focus on a special group of muscle diseases called mitochondrial myopathies.
“Nevertheless, I find it rather paradoxical that the HFEA will have awarded a licence for research whose clinical application, which will alter the germ line of the baby, is by their own definition unethical.”
Peter Braude, an embryologist at King’s College London, said: “I am delighted to hear that this important work will be pursued in the UK, and that the HFEA have had the wisdom to license it.
“Performing the research using donated eggs will help understand whether the process is achievable and safe. They are responsibly doing the needed experiments on cleaving embryos in vitro first, before trying it out on patients. If it works and is safe it will be the answer to the prayers of those inflicted with these awful mitochondrial genetic disorders, for which there is no treatment.”
Andy Miah, a medical ethicist at Paisley University, said: “Many of the more controversial ethical concerns arise only if we project into the future and imagine that a child were to be born, as a result of this kind of procedure.
“Indeed, it is useful to consider this difficult case, even though we are still not yet there. So, even if a child were born with ‘two mothers’, I doubt very much that we should be concerned about its welfare any more than we are concerned about the welfare of all children.
“For those who would see this as a threat to the family unit, we should endeavour to persuade them that reproductive technologies could encourage a greater acceptance of diversity in our society.”
Virginia Bolton, a consultant clinical embryologist at Guy’s Hospital in London, said: “This is yet another example of the value of human embryo research to establish the safety of a technique before it is introduced into clinical practice.”
David Harrison, of the Muscular Dystrophy Campaign, which is funding the research by the team in Newcastle, said: “The innovative approach being tested by Professor Turnbull may lead to a treatment for mitochondrial myopathies, a group of conditions that dramatically affect quality and length of life.”
I feel sick. How long Lord?
Agreed, I say stop playing GOD. GOD created us all the way HE wanted us. Stop trying to re-create what GOD already created perfect. The disorders just make you unique, you may not like it but it's still a part of who you are. I understand if you don't want your kids to have the same thing, but you're alive and well they will bw just fine. I have Asthma and my life has not been "normal" according to those who don't have it . I can do a lot of what they can't and everything they can. I also have ADD, NOT ADHD for those of you who confuse the two. I inherited it from my Pops and it has been a difficult road but I fought through it. Yeah my disorders aren't as horrific as most peoples but I know that if you fight you will overcome your weakness. Anyway, that's my O.P.
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