Preimplantation Genetic Testing (PGT)
This involves the biopsy of the 4 to 6 trophectoderm cells of the day 5 Blastocyst embryo. These cells are the outer cells of the embryo which later on, becomes the placenta to support the pregnancy without damaging the inner cell mass of the embryo the TE Cells are carefully removed and sent to genetics lab for NGS testing and the embryo is safely cryopreserved for future transfer into the mother's uterus. The entire procedure of testing is carried out under sterile conditions, using three compartmentalized and isolated rooms, thus preventing contamination, reducing error, and ensuring accurate reporting. After the testing, the PGT report defines as to which embryo is normal or abnormal for that particular patient and which embryo is recommended to be transferred to achieve pregnancy. PGT can be done for three indications:
PGT A
This is done to screen for aneuploidies in embryos, such as autosomal trisomy (13, 18, 21 are the commonest) or monosomy inembryos. This is carried out in patients with advanced maternal age (>35 years) who are undergoing IVf or in patients who have had repeated IVF failures (2/3 or more) or in patients with repeated pregnancy losses (2/3 or more). In recent times, many patients who are undergoing IVF want to have a single genetically tested normal euploid Blastocyst embryo transfer. This is resulting in higher pregnancy rates, nearly zero multiple pregnancy rates (thus eliminating problems of premature delivery) and patients getting pregnant faster by achieving pregnancy in the first or second Embryo transfer.
PGT SR
This is done in patients with parents being carriers of Balanced Translocation or Robertsonian translocation, in which there is a structural Rearrangement of the chromosomes. Many of these patients present clinically as recurrent pregnancy losses or may also deliver at term with balanced translocation.
PGT M
In this, the embryo is tested for monogenic disorders such as Thalassemia, Sickle cell anemia, cystic fibrosis (generally associated with azoospermia)or 300 plus such single gene defects. This can be also offered for creating a second sibling for the first affected child. For example, if you have a previous Thalassemia affected child, you can do IVF, create embryos and test for an embryo which will HLA match the first child’s bone marrow and which will also be free of the disease. Once the second child is born, its bones marrow can be used to treat the first child. This PGTa can also be offered to patients whose family members may be suffering from gene causing heredity cancers. In the future, a new technique (presently under research, called PGT- P (P for Polygenic disorders) will be used to identify embryos with less chance of transmitting Diabetes, cardiac problems, strokes and general cancers).
PLEASE NOTE THAT ALL PATIENTS WHO CONCEIVE AFTER PGT HAVE TO CONFIRM THE GENETIC STATUS OF THE FETUS BY DOING ANTENATAL /PRENATAL GENETIC TESTING
