Chromosomal Syndromes and Genetic Disease - Research Paper Example

Should the development of fetal DNA-based prenatal screening be continued to meet its full potential? It is understandable that a pregnant woman would want her child to come out healthy. Health providers promote a monthly prenatal check-up in order to determine whether the fetus is growing normally or to watch out for danger signs of complicated pregnancy. However, despite the presence of prenatal genetic testing for more than half a century already, its costs and risks have limited its use to high risk pregnancies, such as those for women aged 35 years and above (Greely 289-290). Taking it to the next level, the technology to sequence fetal DNA in a pregnant woman’s bloodstream significantly facilitates the safe and efficient screening for the presence of mutations that can cause abnormalities to the fetus (Hayden 440). This mode of prenatal screening provides the advantage of knowing as early as the third month of pregnancy the likelihood that the fetus has the genes that code for congenital abnormalities, which significantly affects its growth and development during gestation and after birth. It is believed that the number of conditions that can be detected non-invasively will continue to increase. In fact, Gene Security Network and Sequenom, Inc. are currently developing tests to expand testing for other genetic abnormalities (Hayden 440). This state-of-the-art procedure thus provides the promise of being able to detect predilection of the fetus to any condition, whether it will manifest in childhood or adulthood. Advanced, prenatal screening, if it achieves its full potential of detecting any condition, whether fetal aneuploidy or risk of developing cancer, will provide the best evidence to which parents can base their child-rearing plans from. Thus, this paper supports further development of the non-invasive, prenatal, advanced, fetal DNA-based screening starting at ten weeks of pregnancy, so that in the future all conditions with genetic predisposition can be screened for. Better outcomes is more available for all pregnancies Better health outcomes can result from early intervention to potentially dangerous pregnancies and better preparation for child-rearing that can be achieved through early detection provided by advanced prenatal screening. Early response to potentially dangerous pregnancy Developers should be allowed to further add onto the technology the screening for the presence of fetal DNA mutations that can result to premature termination of pregnancy or failure to thrive that cannot be prevented, so that early detection of such conditions can protect the couple from undergoing a futile or potentially dangerous process of full-term pregnancy. In fact, not more than 5% of monosomies, such as Turner’s syndrome, survive to birth. Polyploidies, either tri- (69 chromosomes) or tetraploidy (92 chromosomes) result to spontaneous abortions or newborns with short survival time (Luthardt and Keitges 1-2). Meanwhile, for high risk pregnancies, in which treatment is available, their early detection leads to early intervention to prevent the associated complications during pregnancy. An evidence of such benefit is the now commonly conducted fetal blood-type screening, which determines whether the fetus carried by a Rhesus (Rh) negative mother has red blood cells (RBCs) that are Rh positive. If positive, the mother can then be given anti-anti-Rh antibodies to prevent the mother’s antibodies from destroying fetal RBCs. Other treatable diseases that can be detected using fetal DNA are cystic fibrosis, sickle-cell anemia and Tay-Sachs disease (Greely 290). All of these are in support of the World Health Organization’s call for preventing maternal deaths, which is prevalent, especially in developing countries. Early preparation for atypical children Detection of non-fatal structural, metabolic or mental abnormalities early during the pregnancy can help the mother and her partner to prepare for the financial and emotional strain that may come with the treatment, rehabilitation and raising of the atypical child. While still pregnant, the parents can already seek medical advice regarding their unborn child. They can join support groups that can help them emotionally in accepting the outcome of the pregnancy. From these, they can hear the experiences of the families having children with the same condition, so that they will know the best possible way to care for the child once it is born. For example, trisomy 21, or an extra copy of chromosome 21, causes Down’s syndrome, which presents with mental retardation, upward slanting of the eyes, flat nose, large tongue, or early death. If detected through prenatal screening, the family can already financially prepare for surgery if gastrointestinal blockage or fatal heart defect is present in the born child. They can be taught early on the special precautions in caring for a child with Down’s syndrome, such that the baby should be well supported and fully awake while breastfeeding. They can plan for the child’s activity and diet, as they are at risk of being obese. Parents and caregivers can already undergo behavioral training to deal with frustration and anger, as well as encourage independence. They can also plan ahead speech, physical and occupational therapies that can help the child as it is growing older (Kaneshiro). In a study conducted by Skreden, et al. (2193), although prenatal diagnosis of congenital anomaly increased parental psychological distress immediately after birth compared to parents who received postnatal diagnosis, 9-year follow-up on these families showed that there was no significant differences in psychological responses comparing parents with and without the benefit of prenatal diagnosis of their child’s condition. This means that in totality it is still more beneficial to get a prenatal diagnosis, since they can prepare much better without an increase in long-term distress. Furthermore, it was observed that intrusive stress continuously decreased until 6 months after birth, only to increase again at 9 months postpartum. Increase in psychological distress at 9 months postpartum can be predicted by unemployment and low educational level. Possibly, these factors can cause hindrance to financially supporting the special needs of the child, which can be more easily prepared for if given more time, as is provided by prenatal diagnosis. Safe and efficient procedure for all pregnant women Certain procedures, despite bearing great promise, do not become commercially available because of its lack of safety efficiency. Fortunately, the potentials of fetal DNA-based prenatal screening can easily be realized because of its safety and efficiency. Currently, the prenatal screening using ultrasound and blood protein markers can correctly detect 90-95% of cases. There are thus a significant 5-10% of tested women that can have false positive results. Fetal DNA-based prenatal screening, which uses maternal blood, can then be used after a positive screening result before undergoing a riskier amniocentesis or chorionic villus sampling, which extracts amniotic fluid by piercing a needle through the belly. A study sponsored by Sequenom, Inc. found that the false positive rate is decreased to 0.2%. Briefly, DNA fragments to identify fetal chromosome 21, which should only make 1.35% of the total maternal and fetal DNA in mother’s blood. An increase in chromosome 21 is an indication of Down’s syndrome. In contrast to amniocentesis, there are few to no contraindications to performing fetal DNA-based screening (Hayden 440). Recently, it has already been proven that advanced newborn screening is a safe and effective technology that results to better health outcomes. In fact, the California Technology Assessment Forum (CTAF) composed of a multidisciplinary group of healthcare providers, researchers, ethicists and consumer advocates, have agreed that prenatal advanced screening for fetal aneuploidy, trisomy 21 and trisomy 18 in high risk women, specifically that offered by Sequenom, Inc., is a safe technology that results to better health outcomes of both child and the mother. The MaterniT21 PLUS test by Sequenom, Inc. is one of the commercially available prenatal screening techniques that can be performed using the mother’s blood sample as early as 10 weeks gestation (“California Technology…”). Prenatal screening does not justify abortion Those against the development of advanced prenatal screening argue against the detection of non-fatal fetal conditions, because finding out that the pregnant mother is carrying anything less than a healthy child can result to great emotional stress that can harm the pregnancy or push her or her partner to decide to abort the pregnancy (Hayden 440; Skreden, et al. 2193). Although plausible, the development of prenatal screening does not support baseless abortion. It just provides an advantage for parents to have a better idea of what is coming to them. If, indeed, after seeing the results of the screening a pregnant woman feels she is physically, financially and emotionally incapable of raising a special child, then whether or not she aborts the pregnancy as a solution is an entirely different issue, simply because bad news from prenatal screening does not automatically mean abortion of pregnancy. As indicated above, there are other options available, such as getting medical advice or joining support groups. Regulated prenatal screening is an important clinical tool Admittedly, the concerns regarding increased abortion, the message of worthlessness of disabled individuals, decreased practicality of treatment and support for those with disabilities, and trait selection are valid. However, those concerns are not enough to totally impede the development of this technology, especially because there are still a vast number of untreatable fatal diseases, prevention remains to be the only cure. What should be done is to regulate its use (Greely 290). References Greely, H. T. (2011). Get ready for the flood of fetal gene screening. Nature, 469, 289-291. Hayden, E. C. (2011). Fetal gene screening comes to market. Nature, 478, 440. Kaneshiro, N. K. (2012). “Down syndrome.” U. S. National Library of Medicine., 16 May 2012. Web. 3 Nov. 2012. Luthardt, F. W. & Keitges, E. (2001). Chromosomal syndromes and genetic disease, Encyclopedia of Life Sciences, 1-12 Skreden, M., Skari, H., Malt, U. F., Haugen, G., Pripp, A. H., Faugli, A., & Emblem, R. (2010). Am J Med Genet Part A, 152A, 2193-2202. “California Technology Assessment Forum Recommends Use of Cell-Free DNA Technology as Advanced Prenatal Testing for Pregnant Women at High Risk for Fetal Chromosomal Anomalies.” Sequenom, Inc., 18 Oct. 2012. Web. 2 Nov. 2012. Read More