Genetic testing during pregnancy

Genetic tests during pregnancy are usually carried out in order to check for any abnormalities in the child itself, and to ensure the safety of both the foetus and mother. Genetic tests look mainly for the presence of mutations, chromosome abnormalities, or genetic disorders (Cunniff, 2004). Traditionally, the major focus was on chromosomal abnormalities (Lau and Leung, 2005), in particular Down’s Syndrome. This procedure would involve looking at the chromosomes using karyotyping (Stanford et al, 2006).

There have been major breakthroughs over the past few decades and more sophisticated tests now exist for a variety of different mutations, disorders and diseases during pregnancy. This has extended to tests before implantation as well, due to New Reproductive Technologies (NRTs). In order to carry out these genetic tests, cells are usually take from the foetus using invasive procedures. These procedures range from amniocentesis and chorionic villus sampling (CVS), as well as celocentesis (Lau and Leung, 2005), to foetal bloody sampling, biopsies and microarray.

The procedures are potentially dangerous and could result in foetal loss. This danger is just one of the many ethical issues on the grounds of which people object to genetic tests during pregnancy. By looking at the spectrum of disorders and diseases that genetic tests can be carried out for during pregnancy and the implications of testing for them, to the implications of new technologies that are being created enabling tests for other traits as well, the essay aims to outline the purposes for such testing and the ethical issues raised by genetic tests during pregnancy.

The topic will be expanded to look at one neonatal test, the Guthrie test for phenylketonuia to illustrate one of the main purposes of genetic screening, and pre-implantation diagnosis, for example tests during in-vitro fertilization (IVF), as this is the real ethical battleground of the future. Most pregnant women are offered a variety of screening tests and, where it is deemed appropriate, specific diagnostic tests as well (Human Genetics Commission, 2006).

Prenatal diagnostic tests provide diagnosis of particular conditions the baby may have (Ibid), and are carried out when there is a ‘familial, maternal or fetal condition that confers an increased risk’ (Cunniff, 2004). Prenatal diagnostic tests will often be carried out if there are abnormal results to screening or other tests (Ibid). None of these tests, however, are entirely reliable (Human Genetics Commission, 2002), and whilst undergoing them it is important that the patients make decision in full knowledge of this fact.

Spina bifida is associated with certain chromosomal abnormalities, and can cause severe disabilities and death. Amniocentesis is used to obtain foetal cells from the amniotic fluid, which can then undergo ‘fetal chromosome analysis’ (Cunniff, 2004) to determine whether the child might have spina bifida. This is most commonly performed between fifteen and eighteen weeks of gestation (Ibid), and though there are risks of miscarriage, they are not high. Maternal serum screening and chorionic villus sampling may also be used for an earlier diagnosis at between ten and twelve weeks.

Some clinical trials have indicated that chorionic villus sampling may result in a slightly higher foetal loss rate than amniocentesis, but ‘earlier diagnosis provides additional time for counseling and decision-making’ (Ibid). In the United Kingdom, abortion is illegal after the twenty-fourth week of pregnancy, with certain exceptions. One of these exceptions is a ‘substantial risk that if a child were born… it would be seriously handicapped’ (Human Genetics Commission, 2006). Each year there are around 1, 900 terminations due to a foetus having a severe disability or handicap (Ibid).

Spina bifida is considered one such serious handicap and a couple can choose to terminate a pregnancy on these grounds if they discover that their child will have it. Many religious groups disagree with the concept of aborting on these grounds as they consider it the will of God. It is often debated, however, that it is likely that spina bifida will result in death anyway, and it would be far worse if a child and parents had to live with the disability for several years before then suffering loss anyway.

On the whole there is a general consensus that it is acceptable to allow these tests in order to give the option of termination, or even the option of treatment such as foetal surgery (Cunniff, 2004) though such treatments hold risks. Cystic fibrosis is a hereditary disease due to over one thousand gene mutations. Up until now molecular tests were carried out using samples obtained through invasive methods and the polymerase chain reaction (PCR) to replicate the genes. These methods unfortunately are neither time nor cost efficient (Lau and Leung, 2005).

Whole human genome microarray, a form of gene-chip technology, is another possible test for genetic defects. This allows comparisons between normal genes and those with a particular disease and may enhance prenatal diagnosis of diseases such as cystic fibrosis (Ibid). Advancements in gene-chip technology in the foreseeable future will allow the study of thousands of mutations in one experiment (Ibid), and thus the identification of huge numbers in society who have or are heterozygous carriers of a specific disease or disorder.

Though there are advantages in that genetic testing would take less time, and people would be able to take preventative measures and treatments, if the information that were gained through any one of the prenatal genetic tests outlined were available to insurers or employers it could be misused (Human Genetics Commission, 2002). One of the purposes of genetic testing is to enable preventative treatment for certain conditions or diseases if an individual is aware that they have the genetic trait that predisposes them to it (Lau and Leung, 2005).

Phenylkentonuria is an autosomal recessive disease caused by the absence activity of the enzyme phenylalanine hydroxylase (McConkey, 1993), which converts phenylalanine into tyrosine (Ibid). The disease can cause neurological damage and mental disabilities if not detected and treated. Fortunately, if the disease is detected an infant can be put on a special diet that prevents any serious or permanent damage, and allows them to live a normal life. Though it is possible to predict whether a child is likely to have phenylketonuria if it is present in the family, tests for it cannot be carried out during pregnancy.

The concentrations of phenylalanine are normal even in foetuses that are homozygous for the disease (Ibid), because proteins pass across the placenta from the mother who can convert phenylalanine to tyrosine in her own liver (Ibid). Blood tests, known as the Guthrie test, are carried out shortly after birth, which detect the disease and allow for preventative measures and treatment. There is very little that could be considered controversial about the Guthrie test as it does not create any great risk for the child or mother, does not provide potential reasoning for abortion, and can be beneficial in preventing the disease from developing.

The only potential ground for ethical battle is over the possibility that if the information about an individual’s test results were to be leaked and misused it could hinder their opportunities, and this could be argued in regard to any confidential or personal records. Down’s Syndrome, or Trisomy 21 as it is also known, is the result of a non-disjunction error resulting in a third chromosome 21.

For women of thirty-five years or older, there is a greater risk of an abnormal number of chromosomes in the foetus (Cunniff, 2006), and samples can be taken through amniocentesis, CVS or blood sampling to test among older women or if a possible abnormality is detected through an ultrasound screening. Foetal blood sampling is useful in these circumstances, as it may be used for ‘rapid fetal karyotyping’ (Ibid). The risk of loss, however, is between 1% and 2%, making it more dangerous than amniocentesis or CVS and giving another reason for objecting to the procedure.

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Although genetic testing can benefit society in numerous ways, such as the diagnosis of vulnerabilities to inherited diseases and ancestry verification, it also has the precarious capability to become a tool in selecting a more favorable genetic makeup of an …

Although genetic testing can benefit society in numerous ways, such as the diagnosis of vulnerabilities to inherited diseases and ancestry verification, it also has the precarious capability to become a tool in selecting a more favorable genetic makeup of an …

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