Preimplantation Genetic Diagnosis
Preimplantation genetic diagnosis (PGD) involves screening single cells from embryos for genetic diseases and chromosomal disorders. This testing is performed with in-vitro fertilization (IVF) and occurs prior to embryo transfer, before a pregnancy is established. PGD offers at-risk couples the opportunity to select embryos for transfer based on their genetic and chromosomal status.
The goal of PGD is to identify abnormal embryos so they will not be transferred, leaving unaffected embryos to be selected for transfer that are more likely to make healthy, and disease-free babies. PGD can identify the presence of chromosomal translocations (rearrangements of parts of chromosomes) and single-gene disorders (genetic diseases that are the result of a single mutated gene).There are over 4,000 single-gene disorders. The most common diseases tested for are Cystic Fibrosis, Tay Sachs, Fragile X, Myotonic Dystrophy and Thalassemia. PGD technology can also be used to determine the sex of the embryo prior to the transfer into the uterus. Sex selection is offered to couples interested in family balancing who already have at least one child.
Who should have Preimplantation Genetic Diagnosis
Preimplantation Genetic Diagnosis is an extremely useful tool for couples in which one or both of the partners are carriers of an inherited genetic disorder. Preimplantation Genetic Diagnosis significantly reduces this risk. Preimplantation Genetic Screening, on the other hand, may only be beneficial for a specific population of patients. This includes patients of advanced maternal age and women with a history of recurrent pregnancy loss. Patients must have a large number of good quality embryos in order for Preimplantation Genetic Screening to improve their outcome.