What is the difference between Preimplantation Genetic Diagnosis (PGD) and Preimplantation genetic screening (PGS)?
Preimplantation Genetic Diagnosis or PGD is the technique of identifying genetic defects in embryos created through in vitro fertilization (IVF) before pregnancy. It is used when one or both sets of parents have a known genetic marker that could indicate some kind of abnormality and/or have a previous child affected by a genetic disease for which one/both parents are carriers of the disease. The embryo is tested to ascertain if it is affected with the disease. While there are definite advantages of PGD and it has reduced the chances of certain genetic disorders, it cannot completely eliminate it. Besides in some genetic diseases, the symptoms and markers do not begin to show till much later in life and it is still very important to have prenatal testing. Preimplantation genetic screening or PGS also known as aneuploidy screening is a procedure in which the genes of embryos created through in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) are examined for ch