Genetic analysis of blastocyst can be done using the technique of PGT A (preimplantation genetic testing for aneuploidy). In this the embryo is biopsied and 3-4 cells of biopsy are sent for genetic analysis. We have our own in-house genetic testing using the S5 Ian Torrent Next Generation Sequencing. The blastocysts post biopsy are frozen on single individual straws, which are numbered. The report of NGS comes in 1 -2 months. After two months we can transfer a single euploid (genetically normal) blastocyst. This can result in high pregnancy rate, with singleton pregnancy and low miscarriage rate. PGT is specially helpful in couples with multiple implantation failures by selecting genetically normal embryos and thereby decreasing the time taken to pregnancy. PGT-A formerly called PGS ( Preimplantation genetic screening) is also offered to women > 35 years of age who desire for single embryo transfer as the risk of aneuplodies increase with age . It can also be offered to patients who have history of recurrent first trimester miscarriages.
Patients who require pre-implantation genetic diagnosis for genetic disorders like thalassemia, sickle cell anaemia, balanced translocation, spinal muscular dystrophy and fragile x syndrome will also need to undergo trophectoderm biopsy, freezing of biopsied blastocyst, testing the cells using NGS, identifying and transferring normal embryo in subsequent embryo transfer cycles. we already have helped few patients of thalassemia and sickle cell anaemia to have normal babies following PGT M
Non Invasive Chromosomal Screening of Embryos
Recently We have introduced a new technique of Non invasive chromosomal screening (NICS) in our lab. This is similar to PGT A in all the steps except the biopsy procedure . In this instead of taking a biopsy, the DNA that has leaked from the embryo into the surrounding culture media is extracted, amplified (using a specially patented Malbac technology) and then tested using our in house NGS system. This is not as accurate as traditional PGT A, however it helps us to choose embryos without touching them or biopsying them .