The primary goal of PGT is to identify genetic defects in embryos created by IVF before transferring them to the uterus, thus decreasing the possibility of pregnancy terminations and births with genetic abnormalities.
There are three types of Preimplantation Genetic Testing:
- Preimplantation genetic testing for monogenic (single-gene) disorders (PGT-M)
- Preimplantation genetic testing for structural rearrangements (PGT-SR)
- Preimplantation genetic testing for aneuploidy (PGT-A)
Like many new technologies, PGT raises some ethical issues, but it also provides a chance for couples to have a healthy family.
There are three types of Preimplantation Genetic Testing:
Preimplantation genetic testing for monogenic (single-gene) disorders (PGT-M)
The goal of PGT-M is to establish a pregnancy that is unaffected by specific genetic characteristics, such as a known heritable genetic mutation carried by one or both biological parents. It is also used to select embryos for transfer that have specific characteristics, such as a particular gender or compatible human leukocyte antigen complex type.
Preimplantation genetic testing for structural rearrangements (PGT-SR)
The goal of PGT-SR is to establish a pregnancy that is unaffected by a structural chromosomal abnormality (translocation) in a couple with a balanced translocation, or deletion/duplication. New technology may actually distinguish normal noncarrier embryos from balanced carriers
Preimplantation genetic testing for aneuploidy (PGT-A)
(formerly called preimplantation genetic screening [PGS]) – The goal of PGT-A is to identify embryos with de novo aneuploidy, including subchromosomal deletions and additions (duplications), in embryo(s) of couples presumed to be chromosomally normal. Theoretically, avoiding transfer of these embryos will reduce the risk of miscarriage and complications related to pregnancy failure and improve the probability of conceiving a viable pregnancy.
How is PGT done?
PGT begins with counselling of the couple. If clients are candidates and desire to proceed, an IVF cycle is initiated and few cells are removed from the embryos and analysed for the condition in question. The healthy embryos are then transferred to the uterus.
Common diseases for which PGD is performed include sickle cell disease, cystic fibrosis, muscular dystrophy and haemophilia. PGD allows us to avoid having children with these and other devastating illnesses.
Although controversial, PGD has the capability of being utilised for sex selection for family balancing