The blastocyst can be geneticallyanalysed using the technique of PGT A (preimplantation genetictesting for aneuploidy). In this the embryo is biopsied. The 3-4 cells of biopsy are sent for geneticanalysis. We have our own in-house genetictesting using the S5 Ian Torrent Next Generation Sequencing. The blastocysts are frozen after biopsy 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 (geneticallynormal) blastocyst and obtain very high pregnancy rate, with singleton pregnancy and low miscarriage rate. PGT is helpful in couples with multiple implantation failures in selecting geneticallynormal embryos and thereby decreasing the time taken to pregnancy PGT-A formerly called PGS ( Preimplantation geneticscreening) is also offered to women > 35 years of age who desire for single embryo transfer as the tisk of abnormal baby increase with age . It can also be offered to patients who have history of recurrent first trimester miscarrages.
Patients who require pre-implantation geneticdiagnosis for geneticdisorders like thalassemia, sickle cell anaemia, balanced translocation, spinal muscular dystrophy and fragile x syndrome will also need to undergo trophectoderm biopsy, freezing of Blastocyst, testing the cells using NGS 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
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 .