Preimplantation Genetic Diagnosis and Screening (PGD/PGS)

The Fertility Center at NYU Langone is an internationally renowned leader in the application of preimplantation genetic diagnosis and preimplantation genetic screening, commonly referred to as PGD and PGS. These techniques were initiated by NYULMC FC Program Director, Jamie Grifo, MD, PhD who in 1992 conducted PGS that resulted in the first American baby born using these procedures.

PGD and PGS are terms used to describe testing an embryo for a specific genetic disease it is at risk of inheriting from the parents. PGD is generally the diagnosis of a single gene defect in the embryo for couples that have a single gene mutation and want to ensure that their offspring won’t carry the disease. Generally this group of patients has a 25 to 50% risk of transmitting a significant medical illness to their child.

PGS generally refers to the screening of chromosomes for aneuploidy (an abnormal number of chromosomes). PGS is the term used more often by reproductive endocrinologists when discussing infertility with couples struggling with issues involving age, repeated in vitro fertilization (IVF) failures, recurring miscarriages, or having had pregnancies that were genetically abnormal.

At NYUFC we use PGD to refer to single gene disorders and PGS to refer to the detection of chromosomally abnormal embryos. In patients carrying disease-causing single gene mutations, we recommend also testing for both the single gene defects as well as aneuploidy because we can do both at the same time. Some of the single gene disorders indentified using PGD include:

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  • Cystic Fibrosis
  • Hemophilia
  • Huntington’s Disease
  • Marfan’s Disease
  • Muscular Distrophy
  • Thalassemia
  • Tay Sachs
  • Spinal Muscular Atrophy
  • Sickle Cell Anemia

On the other hand, PGS identifies embryos containing chromosomal abnormalities that result in IVF failure, miscarriage or babies born with Down’s syndrome (Trisomy 21) or Edward’s Syndrome (Trisomy 18).

Both PGS and PGD involve testing cells from embryos. It is possible to detect genetic irregularities in embryos prior to embryo transfer and affords an opportunity to test the embryos that we select for transfer. Several cells are removed from the trophectoderm (cells destined to be the placenta) of a blastocyst (5-6 day old embryo) and tested for abnormalities. At this early stage in development all embryonic cells generally have the same genetic make-up and potential for development. After biopsy and testing of the embryo’s genetic material, embryos may be selected based on their absence of irregularities.

The advantages of genetic testing include increased chances of pregnancy, decreased chances of multiple pregnancies, decreased chances of pregnancy loss, and the ability to avoid undesired genetic traits.

At NYULMC FC, we discuss all above considerations on an individual basis, giving the utmost attention to all factors involved in any fertility issue. Prior to making any decision about genetic testing, we thoroughly review each patient/couple’s history and offer the most incisive and least invasive course of action.

The benefits of Preimplantation Genetic Screening explained by Dr. Jamie Grifo in his presentation "Single Thawed Euploid Embryo Transfer (STEET)" from the 2013 Fertility Planit Symposium (Video)

PGD/PGS News at the Fertility Center at NYU Langone