Preimplantation Genetic Diagnosis and Screening
PGD = Preimplantation Genetic Diagnosis
PGS = Preimplantation Genetic Screening
For couples who are carriers of genetic conditions and who do not have any actual fertility issues, PGD can be used. In this method, one or two blastomeres are removed at the eight-cell embryonic stage for genetic examination. During this examination, the embryos continue to grow. Only those embryos that are not carriers of the specific genetic condition being investigated are returned to the womb. This is a way of avoiding diseases such as Duchenne muscular dystrophy or Huntington’s disease, and moreover of removing them for good from the family tree. For example, this technique has also been used recently in families with the inherited form of breast cancer. However, an obvious problem is that not all genetic conditions can be traced within the short time frame available (2 days) in one or two cells.
In PGS, the chromosomes are examined at a more general level by means of one or two blastomeres that are also removed at the eight-cell stage. In this way, chromosomal abnormalities such as Down’s syndrome can be avoided. For example, if implantation repeatedly fails, an increased incidence of chromosomal abnormalities is sometimes found. PGS may offer a potential solution here.
The selection of sex can also be done in this way, but in Belgium it is strictly limited by law to medical indications (for example, inherited conditions that are closely related to sex). ‘Designer babies,’ as they are known, are not possible at present, and in any case there is not yet any legal framework that would allow such selection.
Do not hesitate to contact us for further information about PGD and PGS or any other fertility treatment.
We will gladly help you.