PGS vs. PGD

Although these terms are sometimes used interchangeably, PGD and PGS refer to different types of genetic testing performed on embryos created during IVF.

PGD, or preimplantation genetic diagnosis, is the term used to describe testing for a specific genetic disease that an embryo is at risk of inheriting from the parents. PGD is relevant for carriers of genetic diseases, such as Cystic Fibrosis and Tay-Sachs disease. See GSN’s Single Gene clinical trial page for more information.

PGS, or preimplantation genetic screening, is a newer term which refers to the screening of chromosomes for aneuploidy (abnormal number of chromosomes). Aneuploidy occurs by chance and is not inherited. GSN’s 24 Chromosome Aneuploidy Screening with Parental Support is the most accurate and comprehensive technology available to perform PGS; FISH and CGH are other, older technologies that you may have heard about.