Embryos containing genetic material from a man and two women have been produced in a project that researchers are hailing as a “ray of hope” for thousands of families troubled by rare genetic diseases that can lead to heart failure, blindness, diabetes and even infant mortality.
The technique used has researchers hopeful that it could be offered to women within three years. But the study is likely to re-spark the debate over the ethics of embryo research and “designer babies.”
Women who suffer from diseases of the mitochondria — the cells inside their eggs that create energy — may have a realistic hope of receiving effective treatment that would save their offspring from debilitating diseases.
Faults in the mitochondria can cause about 150 known diseases. One in 6,500 persons is affected by such conditions, which can include fatal liver failure, strokes, blindness, epilepsy, muscular dystrophy and deafness.
The team of researchers and scientists at Newcastle University has shown that it may be possible to bypass these diseases by replacing the defective mitochondria cells, dubbed “batteries.”
The process begins by taking a fertilized egg from a mother with malfunctioning mitochondria, before extracting the healthy DNA that contains all of the genetic information on how her child will develop.
Next, scientists take a fertilized egg from a second donor mother. The second egg is stripped of almost all of its DNA, leaving just the egg shell containing the healthy mitochondria battery.
The two elements are then combined — the healthy DNA from the natural mother and father placed in the donor mother’s egg — to create a healthy new fertilized egg.
The technique could allow doctors to ensure that genetic defects are not passed from the mother to their children. Many of the diseases passed from the mother to the child have no known cures, and the technique could ensure that the mother and father won’t have to fight with the debate to have children or not.
“A child born using this method would have correctly functioning mitochondria, but in every other respect would get all their genetic information from their father and mother,” said Prof Doug Turnbull, who led the research. “What we’ve done is like changing the battery on a laptop…the energy supply now works properly, but none of the information on the hard drive has been changed.”
The team expressed that less than 0.2 percent of the DNA from the donor mother could be found in the new egg. The team has performed the technique on 80 fertilized eggs. They were all grown in a lab for 24 hours before the exchange was made. Each egg was allowed to continue to develop for another six to eight days to check for problems.
All eggs were donated by couples undergoing fertility treatments. All were unsuitable to be used during the IVF process.
Currently, under the Human Fertilization and Embryology Act of 2009, it is illegal to create babies using embryos which have been manipulated in the laboratory. However, charities called on the government to allow the use of the technique once testing proves it is safe and effective.
A provision within the Act may allow for such a move to be given the go-ahead if secondary legislation was brought by the Health Secretary. But other campaigners said that the creation of embryos using three parents were unethical and warned that long-term consequences were unknown.
Sharon Bernardi, 44, from Sunderland, has a form of mitochondrial disease that she inherited from her mother. The condition has claimed the lives of six of her children, who all died within a few hours of birth. Her only son, Edward, 20, has a form of mitochondrial disease known as Leigh’s disease and needs constant care.
“It will be too late for me but it would be an amazing thing if scientists and doctors can prevent this in the future,” Bernardi told reporters.
A spokesman for the Department of Health said that there are serious ethical considerations that would need to be taken into consideration before any decisions could be made. “Any proposed regulations would be subject to significant public consultation and Parliamentary debate before they could become law.”
The study was funded by the Muscular Dystrophy Campaign, the Medical Research Council and the Wellcome Trust.
The results of the study are published in the journal Nature.
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