What does human life depend on?

Life and death diagnostics

Pharmacon Meran 2002

Pre-implantation diagnosis (PGD) is one of the methods of prenatal diagnosis (PND), but it is controversial and prohibited in Germany. "PGD is not a routine method, not even abroad, but is still in the experimental stage," said Dr. Dieter Schäfer, senior physician at the human genetic polyclinic at the University of Frankfurt, of course.

Many pregnant women and a large part of society accept prenatal diagnostics, for example with ultrasound, chorionic biopsy, amniotic fluid and umbilical cord puncture. The methods are intended to help identify genetic diseases in the unborn at an early stage. In contrast to the established procedures, PGD is only possible after artificial insemination, before the fruit is implanted; for example with in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI), explained Schäfer.

In any case, mature egg cells are first obtained from the follicle after hormonal stimulation of the woman. In IVF, they are then brought together with sperm in a test tube. The fruit resulting from the fusion of egg and sperm cells is later flushed back into the uterus. ICSI is mainly used for severe male fertility disorders. All that is needed is a single sperm, which is injected directly into the mature egg cell in vitro. If PGD is planned, one or a maximum of two cells (blastomeres) are removed from the embryo in the eight- to ten-cell stage, the genetic material of which is reproduced and analyzed. This procedure usually does not harm the fruit; it can be implanted. In the best case scenario, pregnancy will develop.

What is the point of the procedure, which is sometimes referred to as a "quality test"? PGD ​​can reveal familial chromosomal disorders or monogenic hereditary diseases at an early stage. The sex determination can be informative in the case of hereditary diseases which, like Duchenne's muscular dystrophy, are linked to the X chromosome. Often the genome is searched for damage when the parents are older.

If diseases or genetic defects are discovered, the question arises as to whether the fruit should be discarded or implanted. "The PGD is always concerned with decisions about life and death," said Schäfer, turning to the moral aspects. The status of the embryo, whose fate is inextricably linked with the diagnosis, is of great importance.

Schäfer raised questions: When does human life begin and when is it worth protecting? Does tiered protection make sense depending on the stage of development? What does it depend on whether an abortion after PND or discarding the fruit after PGD can be morally justified? Are the severity of the disability, the viability of the child, the reliability of the diagnosis or perhaps even the wishes of the parents decisive?

PGD ​​is also not a completely safe procedure and can produce false positive or false negative results. "We have to point this out to a woman before the examination and discuss possible consequences with her," demanded the doctor in the detailed discussion. Unfortunately, this also happens far too seldom with PND. Doctors would have to provide information about the details a diagnostic method can provide so that a woman can decide whether she wants to know this knowledge. Pressure from society or from insurance companies must be excluded.

Diagnostics and decisions based on them are problematic in diseases that are almost certain to break out, such as Huntington's disease, at an advanced age, explained the speaker. Or with cystic fibrosis, the severity of which cannot be predicted. Or breast cancer, for which a predisposition can be established, but which does not have to be manifest.

Despite the moral concerns that Schäfer addressed, he saw a decisive advantage of diagnosis before pregnancy: It helps to avoid abortions.

> To Overview

© 2002 GOVI-Verlag
Email: [email protected]