PGD & PGS
Pre-implantation Genetic Diagnosis & Preimplantation Genetic Screening
Pre-implantation genetic diagnosis (PGD) is a technique used in conjunction with In Vitro Fertilization (IVF) to test embryos for specific genetic disorders PRIOR to their transfer to the uterus. PGD involves screening cells from a day 5 or day 6 blastocyst for genetic diseases. The goal of PGD is to identify and select embryos without hereditary disease for transfer.
PGD can identify the presence of single-gene disorders (genetic diseases that are the result of a single inherited mutated gene). Additionally, if both parents are carriers for a genetic condition, PGD makes it possible for couples or individuals who have or who carry serious inherited disorders to decrease the risk of passing the disorder on to their child.
PGD technology can also be used to determine the sex of the embryo prior to the transfer into the uterus. Gender selection is important for genetic disorders that are directly linked to the sex of the child.
For PGD to be performed, a couple undergoes an IVF cycle to obtain eggs that are subsequently inseminated and grown in the IVF Embryology laboratory. A highly skilled embryologist uses a sophisticated microscope set-up to extract cells from the embryo. These cells are then analyzed for the particular genetic testing. The results from each embryo are used by the IVF team to determine which of the embryos are affected with the genetic disorder or not. Then the unaffected embryo can then be transferred back to the patient’s uterus or gestational surrogate to attempt a pregnancy.
Preimplantation Genetic Screening (PGS) applies the technology to improve your chances for a successful pregnancy. One of the most common reasons to have PGS performed is the mother’s age, since the risk of having a child with a chromosomal abnormality, such as Down Syndrome, increases as a woman ages. Genetic screening of the pre-implantation embryo can determine whether the embryo could potentially be affected by a chromosomal abnormality. Therefore, the chance of conceiving a baby with a chromosomal abnormality will be reduced by more than 90% after PGS.
Embryos are screened for missing or additional numbers of chromosomes (aneuploidy), which is a leading cause of miscarriage and implantation failure (failure of the embryo to implant into the uterus). The goal of PGS is to identify chromosomally abnormal embryos, so they will not be transferred leaving the chromosomally normal embryos to be transferred in the attempt to achieve a successful pregnancy.
Please note: No single test can accurately predict the risk of all defects in a child. Many birth defects, such as those related to environmental and toxic exposures, and those that are random and unexplained, are not genetically based and may not be detected with genetic screening.
EXAMPLES OF INHERITED GENETIC DISORDERS DETECTED WITH PGD
- Family History of genetic disorders
- Breast Cancer
- Cystic Fibrosis (CF)
- Tay Sachs
- Sickle Cell Disease
- Fragile X
- Muscular Dystrophy
- Hemophilia | bleeding disorders
- Downs Syndrome
- Familial dysautonomia
MOST COMMON INDICATIONS FOR PGD & PGS
- Chromosome Disorder (example/ Down’s Syndrome, Turner’s Syndrome)
- Advanced Maternal Age (women over 35 years of age)
- Recurrent miscarriages
- Congenital Bilateral Absence of Vas Deferens (CBAVD)
- Azoospermia or absence of sperm in semen
- Severe Oligospermia
Please contact us for more information and to schedule a personalized consultation with Dr. Arnold.