Prenatal Genetic Testing

Prenatal is most often considered as concerning the period between conception and birth. Advances in our collective knowledge of the workings of genes, the effects of different alleles at a given gene, and environmental effects on DNA, both in the body and germ line, should incline us to add to the definition of prenatal as “any stage of life when people are tested for their genetic carrier status in order to inform future family planning by themselves or their relatives” (Alderson 231). This widens the scope of prenatal genetic testing and also complicates the controversy surrounding the ethics of the use of the information gathered from such tests. Prenatal genetic testing is a valuable tool and can be useful within established ethical treatments of medical information.

Currently, prenatal care consists of generalized scanning techniques for each patient including ultrasound scans with which fetal development can be measured visually and blood samples from the mother which are examined chemically. If any anomaly is detected in these routine procedures, there are more precise, yet invasive and potentially dangerous, diagnostic tests available including amniocentesis and chorionic villus sampling (CVS). These tests are also offered to pregnant women over the age of thirty-five, as this is an identified at-risk population for genetic and chromosomal defects in offspring. Amniocentesis entails a sampling of amniotic fluid removed from the womb with a syringe and carries a risk of miscarriage, while CVS involves removing cells directly from the placenta breaching the amniotic sac as well, causing bleeding, cramping, and also potential miscarriage. The amniocentesis can be performed after about 15 weeks of pregnancy and CVS is effective at about 10 weeks. (WebMD)

These diagnostic tests are used primarily to detect developmental abnormalities that are often environmentally affected and are only informative once pregnancy is underway when the only courses of action are termination or acceptance. Many women decline to have these tests, the invasive and non-invasive, done for a variety of reasons – religious and ethical ones being foremost. If one has an anti-abortion stance, one is less likely to submit to testing for conditions which have no treatment because they may feel more harmed by the stress of knowing, unmitigated by the chance to educate and prepare themselves for their coming difficulties. Other factors include skepticism of the accuracy of the tests (Li 1139) and not finding their medical provider's explanation of tests to be a useful source of information (Li 1140). Women appear to perceive their clinicians as “more interested in the aspect of controlling pathophysiology” while themselves being more of a nurturing protector (Li 1141).

Encouraging prenatal genetic testing to be done before conception will serve a variety of functions concerning the health of future offspring and potentially reduce the occurrences of medically relevant abortions. There are relatively common conditions that can be tested for in a paired couple that do not individually express a disease but can each carry a recessive allele that may be active in their potential children, such as sickle-cell anemia, Ty-Sachs disease, and thalassemia, a defect in the protein production of hemoglobin. If one finds that she is a carrier, her partner will also need to undergo testing. This sharing of responsibility for a child's genetic well-being appears to make women more relaxed and accepting of the testing because they feel less that they are the sole responsible party to a fetus's health (Reed 351) and allows men to feel more engaged in a process that has hitherto been the domain of the mother alone (Reed 354).

Genetic tests done for future parents can also predict the possibility of passing along rare disorders of which there may be no family history and therefore no reason to suspect that there may be any danger. Lesch-Nyan Syndrome is an “X-linked recessive disorder of purine synthesis” (Young 300) “in which there is defective activity of the enzyme hypoxanthine-guanine phosphoribosyltransferase” HPRT (Nyan 807). The HPRT gene is located on the X-chromosome and, when mutated, leaves the body unable to remove excess uric acid. When the father contributes another X-chromosome for a female child, there is no expression of the disease, but for a male who inherits this mutated gene, there are variants of LNS ranging from mere overproduction of uric acid to the tragic effects of neurological symptoms including severe motor disability, dystonia, spasticity, impulsive spitting, hitting, and cursing, and self-mutilation by chewing, for which the only treatment is immobilization or total tooth extraction (Jinnah 671). Prenatal testing for this disease employs amniocentesis and CVS but has, in at least one case, judged a fetus to be normal that turned out to be affected and is only used for families known to be at risk (Nyan 808). A less invasive and more accurate survey of a woman's genetic code prior to conception would aid in the educated decision of bearing children before implantation of an embryo.

Not every pregnancy is planned and not everyone has the financial wherewithal to afford early genetic screenings. Insurance companies cover most testing done for fetal health after impregnation occurs, though, so effective and safe methods of prenatal diagnosis are being devised. A study in the Department of Transplantation, Jagiellonian University of Cracow, Poland demonstrated proof of concept for separating fetal cells from maternal blood. During pregnancy, blood from the fetus enters the mother's blood stream “resulting in a physiological michrochimerism” (Grabowska S32) and, when isolated, could potentially be used for genetic diagnostic testing (Grabowska S32).

Having exact knowledge of a specific individual's genetic particulars is not a desirable scenario to the entire population. There are fears based on the idea of genetic determinism, privacy issues, and a notion of “playing God” that are pervasive throughout popular opposition to genetic testing. The arguments in the scientific community, however, are focused more on the ethics of gene therapy and germ-line engineering, but these arguments reflect issues with our current knowledge that would lessen the efficacy of large scale prenatal genetic testing. Monogenetic diseases, such as cystic fibrosis or Lesch-Nyan Syndrome, are caused by mutations of single genes and the effects of these mutations are complex, sometimes extreme, and not always completely understood. No one knows why, for instance, a defective HPRT gene causes any neurological symptoms, as it only directly deals with uric acid production and removal (Young 301). The aims of genetic testing are to allow people to make educated decisions involving family planning and lifestyle choices, and to improve health related conditions for the entire population. The overall effects of specific alleles are not certain, though, so there will be doubts when basing reproductive decisions on these tests.

The perception based on genetic determinism that individuals can be discriminated against as a direct result of their specific DNA sequencing is an outright fallacy. In his book “The Extended Phenotype,” the ethologist and evolutionary biologist Richard Dawkins notes that “[t]he belief that genes are somehow super-deterministic, in comparison with environmental causes, is a myth of extraordinary tenacity...” (Dawkins 11). The expression of most traits is a combination of genetic predisposition and environmental moldings. A predisposition is not a determination, but merely a probabilistic potential to react in a specific manner towards a specific environment. Some people who smoke get lung cancer. Some people who have never smoked get lung cancer. It would be unethical for an insurance company to be permitted to adopt policy rates based on genetic codes, due to uncertainty of expression that is the complete opposite of genetic determinism and any information gleaned from such testing should be seen as privileged and protected under privacy laws. In fact, there are 28 states with laws explicitly prohibiting discrimination by insurance companies on the basis of genetic testing (Hall 293).

The philosophical concept of “playing God” may stem from an idea that we have no right to interfere with the natural process of reproduction. This is referred to as the naturalistic fallacy - because something is natural, it is good. Good is sometimes subjective, but, here, it can be viewed as either “as God intended” or as strengthening the gene pool in terms of natural selection. If one views using genetic testing as a decision making tool as being against “God's will,” and following that line of reasoning through to its logical, though absurd, conclusion, one must view all forms of reproductive interference as wrong. Basing family planning on genetic knowledge is not the same as eugenics or even abortion, it is concern for the health and well-being of a potential real person and that demonstrates a level of caring that, though abstract, is deeply commendable. For others, prenatal genetic testing of pre-parenthood candidates is a sort of gentle selection, possibly preventing the spread of the defective genes in a manner more sophisticated than nature.

Prenatal genetic testing, of parents or a fetus, is a revolutionary diagnostic tool useful for education and possibly preventative care. If employed widely and responsibly, it could improve the human condition around the world.

Works Cited

Alderson, Priscilla, et al. "Prenatal screening and genetics." European Journal of Public Health11.2 (2001): 231-233. Academic Search Complete. Web. 21 Apr 2011.

Dawkins, Richard. The Extended Phenotype. Oxford: Oxford University Press, 2008. Print.

Grabowska, A., Majka, M. and Pietrzyk, J. J. "Attempt to devise new, non-invasive prenatal diagnosis method based on fetal genetic material isolation from maternal blood." Reproductive BioMedicine Online. 20 (2010): S32. Academic Search Complete. Web. 31 Mar 2011.

Hall, Mark A. and Stephen S. Rich. “Laws Restricting Health Insurers’ Use of Genetic Information: Impact on Genetic Discrimination.” American Journal of Human Genetics. 66.1 (2000), 293-307. Electronic Journal Finder. Web. 04 Apr 2011.

Jinnah, H.A. et al. “Attenuated Variants of Lesch-Nyan Disease.” Brain: A Journal of Neurology. 133 (2010): 671-689. Electronic Journal Finder. Web. 31 Mar 2011.

Jocoy, Sandy. “Chorionic Villus Sampling.” WebMD.com. 13 May 2008. Web. 24 Apr 2011.

Li, De-Kun, et al. "Factors influencing women’s acceptance of prenatal screening tests." Prenatal Diagnosis 28.12 (2008): 1136 - 1143. Electronic Journal Search. Web. 21 Apr 2011.

Nyan, William L., Linh-Uyen C. Vuong and Robyn Broock. “Prenatal Diagnosis of Lesch-Nyan Disease.” Prenatal Diagnosis. 23 (2003): 807-809. Electronic Journal Search.Web. 31 Mar 2011.

Reed, Kate. "‘It's them faulty genes again’: women, men and the gendered nature of genetic responsibility in prenatal blood screening." Sociology of Health & Illness 31.3 (2009): 343-359. Electronic Journal Center. Web. 21 Apr 2011.

Young, Simon N. and Roberta M. Palmour. “Research on Genes: Promises and Limitations.” Journal of Psychiatry & Neuroscience. 24.4 (1999): 300. Academic Search Complete. Web. 31 Mar 2011.