Pre-implantation genetic diagnosis (PGD) refers to testing embryos for a genetic disorder prior to transfer to the mother. The purpose of the test is to avoid passing the genetic disorder on to future generations.
PGD makes determining which embryos are free of a particular genetic disorder possible. The aim is to ensure that children are born free of the disorder and bring an end to it in the family.
In order for PGD to be carried out, genetic testing of the future parents is necessary.The first step, therefore, is genetic testing. In other words, a process to identify the error in the gene (mutation) which is behind the disorder.Based on the results obtained, the most appropriate way of diagnosing future embryos when in the in vitro fertilisation laboratory (informativity) needs to be designed.
Once the phases prior to PGD (genetic and informativity study) have been completed, the PGD cycle can go ahead with guarantees. To this end, the couple will undergo in vitro fertilisation (IVF) treatment. It is important to wait until the embryos from the treatment have divided so that several embryo cells can be extracted (embryo biopsy). The biopsies are then analysed in the molecular biology laboratory in order to find out if the biopsied embryos are free of the disorder in question. The aim is to transfer healthy and viable embryos which will lead to a healthy pregnancy.
PGD is recommended in couples who have or who are carriers of a genetic disorder and who wish to have a child that is free of that disorder. The technique ensures that only children free of the disorder will be born.
The number of cases in which the alteration causing hereditary disorders is known is greater every day. As such, PGD can be used to analyse any genetic disorder for any known gene error (mutation). It can be applied in the case of: