Preimplantation Genetic Diagnosis presents a solution in assisted reproduction to avoid genetic diseases in births. By observing the embryos, it is possible to select those with the least genetic predisposition to suffer certain pathologies in order to implant them in the uterus with the aim of gestation.
It is a technique used as a complement to the methods of Assisted Reproduction of In Vitro Fertilization and Intracytoplasmic Microinjection of spermatozoa, to select those embryos free of the genetic alteration studied. By means of this selection, the gestation of a child affected by a genetic or chromosomal disease can be avoided.
When is Preimplantational Genetic Diagnosis recommended?
This procedure is performed in case of detection of serious hereditary diseases, of early onset or that do not have a postnatal curative treatment and with the aim of selecting unaffected pre-embryos for transfer. Likewise, it can also be carried out under the detection of diseases or alterations that can put the embryo’s birth at risk.
In the case of other genetic diseases, the parents must request authorization from the National Commission on Assisted Human Reproduction.
In the case of genetic diseases, the couple must previously carry out an informativity study, which consists of searching for genetic markers in the blood by means of an analysis. In case of chromosomal diseases, no previous study is required.
Results of the technique
The effectiveness of the technique depends on the probability of having a sufficient number of good quality pre-embryos. This possibility varies according to the age of the patient, the causes that have determined the indication for PGD and the number of good quality eggs obtained. Thus, the possibility of pregnancy depends fundamentally on the patient’s age and on the number and quality of the pre-embryos transferred, but the pregnancy rate is currently 50.2% per transfer. In short, 80% of pregnancies are obtained in the first three PGD cycles with successful embryo transfer.
Is there any risk involved in Preimplantation Genetic Diagnosis?
There is a risk of damage to a pre-embryo during the biopsy. Due to the complexity of the techniques used, the genetic study presents between 4% and 8% of failures in the diagnosis due to problems in the biopsy, fixation or hybridization processes. In this case it will mean the absence of conclusive results on the genetic composition of the pre-embryos.