- L.S. Rothenberg, M.D.
Division of Medical Genetics, Department of Medicine, University of California, Los Angeles, Box 951736, Los Angeles, CA 90095-1736, USA
Dr. Mueller focuses on one of the potential contradictions, namely that selecting "healthy" embryos through techniques of preimplantation diagnostics is apparently not permitted currently in Germany while, at the same time, abortion of "unhealthy" fetuses (those with inherited genetic disease diagnosed through more conventional genetic testing) is permitted, at least under certain conditions. Other, possibly more profound ethical questions surrounding preimplantation genetic testing exist as well.
Handyside, whose pioneering research at the Hammersmith Hospital in London advanced the clinical success of the technique (3), suggests the presence of at least two major ethical issues involving (a) objections to the manipulation and destruction of human preimplantation embryos and (b) "the use of this approach to screen for genetic defects that would not justify terminating established pregnancies" (4). Suzumori highlights the risk-benefit relationship to the patient by noting the potential damage to the embryo by the manipulation involved in the testing process, the future application of gene therapy or improved techniques to treat affected embryos, the inevitable damage to or death of some blastomeres after they are frozen for storage, the production of multiple embryos for the purpose of experimentation and manipulation [90% of which may be wasted], and the risks associated with the in vitro fertilization and embryo transfer process employed. (5)
Suzumori also mentions the very high economic cost of the procedure (5). To give an example of that cost in the United States, Schulman (whose Genetics & IVF Institute in Fairfax, Virginia, provides such clinical testing) estimates that for a current average charge of US$50,000, preimplantation genetic testing for Huntington disease could be performed for "a couple containing one member at risk for having the Huntington gene" and the couple "could be on average assured of having two unaffected children" (6).
While the emphasis to date has been on single-gene Mendelian diseases such as cystic fibrosis and spinal muscular atrophy and on sex-linked diseases such as Duchenne muscular dystrophy, future use of this technology will inevitably expand to more common polygenic disorders such as cancers and cardiovascular disease and may also include behavioral disorders and psychiatric illness at some point. "Designer babies," Handyside reassures us (4), are unrealistic, but an enthusiasm to eliminate embryos with undesirable genes or genetic mutations and to maximize the parents' combination of existing genes--if they have access to the service--may be quite realistic. This is quite apart from national concerns about (or pressure for) more eugenic goals and the availability of abortion services.
Clearly, we can look forward to challenging ethical discussions concerning this and other types of reproductive technology and genetic testing.
1. Abbott A. European convention allows use of human embryos [news]. Nature 1996;384:298.
2. Macer DRJ. Universal bioethics and the human germ-line. Politics & Life Sciences 1994;14:27-29. See also Macer, Bioethics for the People by the People (1994).
3. Handyside AH, Lesko JG, Tarin JJ, Winston MRL, Hughes MR. Birth of a normal girl after in vitro fertilization and preimplantation diagnostic testing for cystic fibrosis. NEJM 1992;327:905-909.
4. Handyside AH. Preimplantation diagnosis. In: Reich WT (ed in chief), Encyclopedia of Bioethics (rev. ed. 1995), vol. 2, pp. 985-986.
5. Suzumori K. New advances in prenatal diagnosis: implications of the preimplantation diagnosis of genetic disease. pp. 72-75 in Fujiki N, Macer DRJ (eds), Human Genome Research and Society (Eubios Ethics Institute 1992).
6. Schulman JD, Black SH, Handyside A, Nance WE. Preimplantation genetic testing for Huntington disease and certain other dominantly inherited disorders. Clin Genet 1996;49:57-58.