CONTROVERSIAL plans to treat unborn children with gene therapy have been given an even more contentious twist. Under a proposal presented to a US government panel late last month, this therapy would initially be tested on fetuses destined for abortion.
Earlier this year, French Anderson of the University of Southern California in Los Angeles announced that he was seeking approval for fetal gene therapy (This Week, 27 June, p 12). He is still developing the techniques and will not be ready to start trials for at least three years. "We wanted to leave time for lots of public and private discussions," he says.
Anderson pioneered human gene therapy in 1990, when he treated children with a hereditary disorder called severe combined immune deficiency (SCID), caused by the lack of an enzyme vital for the development of the immune system. At a meeting of the National Institutes of Health Recombinant DNA Advisory Committee (RAC) on 24 September, Anderson described how fetuses with SCID would be given healthy copies of the gene for the enzyme. He also outlined plans for in utero treatment of an inherited blood disease called alpha-thalassaemia, caused by a defect in the gene for part of the oxygen-carrying molecule haemoglobin.
One concern is that a fetus's small size means the therapeutic gene has a greater chance of invading reproductive tissue and introducing genetic changes that will be passed down the generations.
But the committee had particular concerns about alpha-thalassaemia, says
Claudia Mickleson, biosafety officer at the Massachusetts Institute of
Technology and chair of the RAC. We each carry four copies of the gene that is
defective in people with alpha-thalassaemia. In the worst cases all four copies
are damaged and fetuses die in the womb or shortly after birth. The mother can
also develop a life-threatening condition called pre-eclampsia, which involves
high blood pressure and fluid retention. "If the therapy
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