All About Preimplantation Genetic Testing

WHO ARE THE GOOD CANDIDATES FOR PGT? Couples with a previous pregnancy or children with an inherited genetic disorder. Women who have had two or more miscarriages due to chromosomal abnormalities. Women who have experienced previously failed embryo implantation Women diagnosed with unexplained infertility. METHODOLOGY The first step is an embryo biopsy. In both forms of testing, the biopsy is at the blastocyst (day five or day 6 of embryo culture) stage of development. TE allows the placenta and inner cell mass (ICM) to develop, which later develops into the baby. Results are usually available within 10 -14 days following the biopsy. Preimplantation genetic testing can be of three types: PGT-A, PGT-M, and PGT-SR PGT-A stands for preimplantation genetic testing for detecting aneuploidy PGT-A analyses embryo cells to determine if there is an average number of chromosomes. Trisomy of chromosome pairs can sometimes result in a live birth, Down syndrome, also called trisomy 21 (an extra chromosome in average pair # 21), Turner syndrome (trisomy 18) and Patau syndrome (trisomy 13). PGT-M stands for preimplantation genetic testing for the detection of monogenic gene disorders PGT-M analyzes a child being born with a genetic mutation. It can also cause an inherited genetic mutation, such as the BRCA1 and BRCA2 mutations, significantly increasing a woman's risk of breast and ovarian cancer. PGT-M examines common disorders, including: Huntington's disease Sickle cell anaemia Muscular dystrophy Cystic fibrosis BRCA1 and BRCA2 mutations Fragile-X syndrome Tay-Sachs disease PGT-SR stands for preimplantation testing for structural rearrangements Preimplantation genetic testing-structural rearrangements are used to test embryos at risk for chromosome gains and losses related to parental structural chromosomal abnormalities (e.g. translocations, inversions, deletions, and insertions). LIMITATIONS Patients and healthcare providers should know that a negative preimplantation genetic test result does not guarantee a newborn without congenital abnormalities. Furthermore, experienced laboratory personnel in IVF and genetics are essential for a patient's success. BENEFITS Euploid embryo transfer results in the highest pregnancy and live birth rates, reducing miscarriage risk independent of maternal age. PGT-M and PGT-SR exclude the affected embryos, preventing the disorder's genetic transmission to the offspring.