PGT(A): This involves the biopsy of the cells of say 5 embryo (Blastocyst). These cells are the outer cells of the embryo which later on, becomes the placenta and thus are not the cells directly involved in making the baby. These 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. This is done to screen for aneuploidies in embryos, such as autosomal trisomy (13, 18, 21 are the commonest) or monosomy in embryo’s. 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).

PGT SR

In this, the embryo is tested for monogenic disorders such as Thalassemia, Sickle cell anaemia, 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).

NICS

Standard Invasive trophectoderm embryo biopsy with PGTa has some risks of damaging the embryo. This problem can be completely avoided using NICS, in which the DNA that has leaked into the culture media from where the Blastocyst is growing, expanding and hatching on day 5/day 6, is amplified and then tested by NGS. This test can be an alternative to the embryo biopsy test of PGTa. The NICS is less accurate (70 – 85 % concordance rate) compared to standard embryo biopsy as far as diagnosis is concerned. However as there is no embryo biopsy involved, it has no possibility of damaging the embryo, and thus no possibility of reducing the implantation potential of the embryos. The indications are similar to that of PGTa