Screening Creates Disease Free Baby
Screening Creates Disease Free Baby
Genetic Selection, Ethical Issues
Date: February 22, 2002
Source: BBC News. 〈http://news.bbc.co.uk/1/hi/health/1842932.stm〉 (accessed December 28, 2005).
About the Author: This news article was written by an unattributed author for the British Broadcasting System (BBC), the United Kingdom's public news service. The BBC provides interactive TV channels, radio networks, and an online news site, all providing local and national news and commentary.
Genetics is one of the most rapidly growing specialties in medicine. Since 1980, research in genetics has added immeasurably to the understanding of the etiology of many diseases by identifying biologically important genes and disease-causing mutations. These data have generated large numbers of new clinical diagnostic assays, the majority of which are performed on peripheral blood or bone marrow of children or adults. The information obtained is used to make a specific diagnosis that leads to appropriate treatment for the patient. But when testing is done prenatally, other choices are possible. If the fetus is affected or potentially affected with a debilitating or life threatening disease, pregnancy termination is an option. Although it is not yet possible to create a "designer" baby (a baby with characters chosen by the parents), it is possible to perform prenatal testing for one or more defined characters. This raises concerns about when, and if, it is appropriate to select or deselect a fetus based on certain "desired" criteria.
A woman has chosen to have a genetically selected baby to ensure it does not develop early onset Alzheimer's disease which runs in the family.
The woman, who is 30 and has not been identified, may be unable to recognize or care for her daughter within 10 years.
She and her family carry a mutation which causes the onset of Alzheimer's disease before the age of 40.
However, the child, who is now about 18 months old, did not inherit the tendency to develop the disease.
Early onset Alzheimer's, a very rare condition, is defined as Alzheimer's—a form of dementia—that strikes before the age of 65.
Researchers at the Reproductive Genetics Institute of Chicago said the baby's birth marked the first time preimplantation genetic diagnosis, as the technique is called, has been used to weed out embryos carrying the defect that causes early onset Alzheimer's.
The little girl is thriving, said Yuri Verlinsky, chief author of the report in this week's Journal of the American Medical Association.
Verlinsky said genetic screening has been used more than three thousand times and is often employed to avoid inherited disorders like sickle cell anaemia.
His clinic was involved in a case last year where an embryo was chosen to provide stem cells to assist a sibling of the unborn child.
Ethical debate While the child's mother is still healthy, her sister developed early onset Alzheimer's at the age of 38, her father died at 42 after suffering psychological and memory problems and one of her brothers began having short-term memory problems at 35.
He said: "I can't speak for the public, but it's a decision of the family and not the public."
In a commentary published in the same journal, Dena Towner and Roberta Springer Loewy of the University of California said the study raised ethical questions.
They said: "Much like her sister, the woman in the report … most likely will not be able to care for or even recognise her child in a few years."
The two doctors said the mother acted responsibly by ensuring that her child will not have to live with the threat of developing early onset Alzheimer's.
However, they took issue with defining her ethical responsibility "solely in terms of disease prevention" without considering that she may not be able to care for her child.
"The differences between these two interpretations of ethical responsibility are stark, but both rest on assumptions made about reproduction—is it a privilege or it is an unquestionable and inalienable right?" they asked.
Ethical issues arise in all areas of medicine, but special attention focuses on genetics, probably because this field explores the transmission of genes within families. In particular, issues associated with prenatal diagnosis seem to be problematic.
Prenatal genetic diagnosis can identify a large number of diseases by evaluation of placental and/or fetal cells. The studies are usually performed between ten and twenty weeks gestation, and the type of study used is based on the parents' age, medical history, and ethnicity. When a known disease or major malformation is identified, the parents have the option of terminating the pregnancy. For a more limited group of diseases, preimplantation genetic diagnosis can be performed. With this technology, eggs removed from the mother are fertilized in vitro by sperm from the father, and the resultant zygotes are cultured to the eight-to-sixteen cell stage. One cell from each is removed and tested, and only "normal" embryos are implanted in the mother's uterus. This technology eliminates the need for termination of an ongoing pregnancy and, thus, is more acceptable to many individuals. Either technique has the effect of selecting a fetus based on specific criteria.
Under what circumstances is this type of selection acceptable? Geneticists use the technology to obtain relevant clinical information on a patient. If the data shows the fetus has a lethal or severely debilitating disorder, termination of pregnancy is considered an acceptable option. Therefore, parents may be offered a choice between continuing or terminating a pregnancy with a confirmed diagnosis of terminal conditions such as anencephaly or trisomy thirteen, or an incapacitating disease such as Tay Sachs, sickle cell disease, or Duchenne muscular dystrophy.
A different dilemma is posed by diseases such as Alzheimer's disease, Huntington's disease, and breast cancer. These are classified as late onset diseases since affected individuals show no signs or symptoms until they are adults. Genetics professionals discourage the use of prenatal diagnosis to select against embryos or fetuses at risk for such disorders since most affected individuals can live a productive life before the disease strikes. However, these diseases are usually progressive, and watching a loved one slowly deteriorate can be devastating for families. Thus, some will chose prenatal diagnosis rather than bringing a child into the world knowing that he or she would have that fate.
An area of genetic selection that is considered unethical by genetics professionals is elective termination of a pregnancy solely because the sex of the fetus is not what the parents desire. This abuse of the system can occur since most prenatal testing provides the sex of the fetus as a courtesy to the parents.
Decisions on what testing to request and how to use the results are often difficult. Geneticists provide counseling, but the final choice rests with the patient. It is critical that all relevant factors be considered before a decision is made. For example, in the case cited above, a question was raised if the mother acted ethically in having a child whom she could take care of for only a few years. But, this should not be an issue if the woman has a partner or family member who participated in the decision to have the child and who will be able to raise the child after the mother becomes incapacitated.
As of January 2006, there are few rules governing genetic selection via prenatal diagnosis, creating a challenge for potential parents and geneticists alike.
Magill, Gerard, ed. Genetics and Ethics: An Interdisciplinary Study. New York: Fordham University Press, 2003.
Verlinsky, Yury, and Anver Kuliev. Practical Preimplantation Genetic Diagnosis. New York: Springer, 2005.
ADEAR. Alzheimer's Disease Education and Referral Center. National Institute on Aging. 〈http://www.alzheimers.org/generalinfo.htm〉 (accessed January 23, 2006).
The Genetics and Public Policy Center. 〈http://dnapolicy.org/index.jhtml.html〉 (accessed January 23, 2006).
PGD: Preimplantation Genetic Diagnosis. A Discussion by the Genetics and Public Policy Center 〈http://dnapolicy.org/downloads/pdfs/policy_pgd.pdf〉 (accessed January 23, 2006).