Preimplantation Genetic Testing for aneuploidy (PGT-A) is a genetic screening that can be performed on the embryos during an IVF treatment, before they are implanted in the womb. It allows detecting abnormalities in the number of chromosomes (aneuploidies) and transferring only the embryos that are chromosomally normal (euploid).
Humans have 46 chromosomes in each cell of their body. Although most embryos cannot survive with a missing (monosomy) or extra (trisomy) chromosome/s and are related to implantation failure or spontaneous miscarriage, some others can survive till birth leading to a baby affected of a genetic syndrome (for example, trisomy 21 related to Down Syndrome). Thus, by screening the embryos for chromosomal aneuploidies we can help couples to:
Different options of chromosomal screening are available: 24-chromosomes, 9-chromosomes (X, Y, 13, 15, 16, 17, 18, 21, 22), 5-chromosomes (X, Y, 13, 21, 18) or 3-chromosomes (X, Y, 21) test.
Chromosomal abnormalities occurred naturally during egg and/or sperm formation or in the first steps of embryo development and can involve any chromosome. However, some specific groups of patients are at higher risk to develop chromosomally abnormal embryos and can preferentially benefit from PGT-A: