In this case study, I will examine an argument which aims to show that, the effort to prevent the effort to prevent the birth of severely disabled children with the use of Preimplantation Genetics Diagnosis (PGD) is morally acceptable and should be contin

Introduction

In this case study, I will examine an argument which aims to show that, the effort to prevent the effort to prevent the birth of severely disabled children with the use of Preimplantation Genetics Diagnosis (PGD) is morally acceptable and should be continued within the society for the right purpose.

What is Preimplantation Genetics Diagnosis?

In medicine and clinical genetics, Preimplantation Genetic Diagnosis (PGD) is a scientific technique which is used to identify genetic defects in the embryo. The process starts with a basic In Vitro Fertilization. For PGD, the early embryo is examined after IVF for inherited disorders or to determine the sex of the embryo for sex-related genetic disorders. ¹

Conditions diagnosed with PGD

PGD is offered for three major groups of diseases, including sex-linked disorders, single gene defects and chromosomal disorders.

Sex-linked disorders- PGD can be used to determine the sex of an embryo in which the specific genetic defect is unknown. Sex-linked recessive disorders include hemophilia, fragile X syndrome, most of the neuromuscular dystrophies and hundreds of other diseases. PGD can also be used for sex-linked dominant disorders such as Rett syndrome, incontinentia pigmenti, pseudo hyperparathyroidism, and vitamin D–resistant rickets. X-linked diseases are passed to the child through a mother who is a carrier. They are passed by an abnormal X chromosome and manifest in sons, who do not inherit the normal X chromosome from the father. ¹

Single gene defect-PGD is used to identify single gene defects such as cystic fibrosis, Tay-Sachs disease, sickle cell anemia, and Huntington disease. In such diseases, the molecular abnormality of the gene is the detected with use of techniques such as PCR. ¹

Chromosomal Disorders- The last group includes chromosomal disorders in which a variety of chromosomal rearrangements, including translocations, inversions, and deletions, can be detected using FISH. Some parents may have never achieved a viable pregnancy without using PGD because previous conceptions resulted in chromosomally unbalanced embryos and were spontaneously miscarried. ¹

Preimplantation genetic diagnosis can also be used for the purpose of gender selection and recurring pregnancy loss associated with chromosomal concerns. ²

Who is PGD aimed at?

PGD is normally aimed at couples who have high risk of having a child with a genetic disorder. Also couples with repeated pregnancy loss and finally couples who wish to identify a tissue match for a sick sibling who can be cured with transplanted cells healthy unused embryos form IVF. PGD can also be offered to couples who have repeatedly been unable to become pregnant through multiple IVF cycles. ²

PGD Procedure

As shown in Figure 1, PGD begins with the normal process of in vitro fertilization which includes:

The woman is given daily medicine by injection in order to stimulate the ovaries to produce more eggs than normal. ²
After two weeks, the eggs are then removed with a small lab instrument known as the pipette and then fertilized with a sperm in the laboratory. ²
After fertilization, the early embryo divides for several days in the laboratory. At approximately 8 cells, it is then ready for biopsy and testing. This is where the PGD procedure begins. ²
A single cell is then removed, which undergoes testing for any genetic disorders. If a disorder is detected, the embryo is then destroyed. The other embryos also undergo testing. ²
Once the PGD procedure has been performed and the embryos free of genetic problems have been identified, implantation will then be attempted through embryo transfer, Intracytoplasmic sperm injection (ICSI), or Zygote Intrafallopian Transfer (ZIFT). ²
As shown in figure 1, PGD can also be done through the FISH procedure.

Figure 1

Arguments for Preimplantation genetics diagnosis

Some people argue that PGD is the best technique which could be used to eliminate incurable genetic disorders.

Advantages of PGD include, this technology can help eliminate genetic disorders in the future such as, Tay-Sachs disease, cystic fibrosis, Huntington disease, X-linked dystrophies and others. Complete cure for these diseases are not yet to be found, therefore preventing the disease is preferable to waiting for the cure to become available.³

Most testing for genetic diseases is currently performed through amniocentesis or chorionic villus sampling when the fetus ...