Preimplantation Genetic Diagnosis

Preimplantation genetic diagnosis (PGD) is a diagnostic test performed with in vitro fertilization (IVF), to find out if the embryo(s) have genetic diseases or chromosomal abnormalities. PGD is the most established advancement in genetic testing to ensure babies are born without genetic abnormalities or diseases. Couples with a family history of serious genetic disorders, or who carry a genetic disease themselves, have successfully decreased the likelihood of having a child with these serious conditions.

PGD Procedure
PGD combines two procedures available at our center:

1. In vitro fertilization (IVF)
2. Genetic analysis of a cell from each embryo in order to identify genetic disorders: The process begins when a single cell is removed from an embryo and tested for genetic problems. This complex testing identifies embryos with common genetic complications. By transferring only non-affected embryos to the mother's uterus, the probability that couples will have a healthy child increases greatly. PGD does not test for every chromosome or genetic defect. PGD is not automatically part of a conventional IVF cycle. This specialized testing must be specifically requested by the patient or recommended by the physician.

Indications for PGD
PGD is recommended for patients who are at risk for serious genetic disorders such as cystic fibrosis, sickle cell disease, or Down's Syndrome. PGD is also helpful for patients with unexplained infertility, recurrent miscarriages, unsuccessful IVF cycles, advanced maternal age, or male factor infertility. In large studies of miscarriages, the genetic defect rate ranges from 50% -80%. Here is an interesting link on NBC's website about miscarriages and genetic defects.

Genetics 101
What are genetic defects and how are they caused?
Each cell in your body contains chromosomes, which contain our genetic material in genes. Each cell has thousands of genes. These are the ingredients that make us who we are. We inherit 23 pairs of chromosomes from our parents. Genetic disease is caused by an abnormality of a gene or entire chromosome (which would affect many genes.) This can occur in many ways, such as absence of a gene, too many genes, or a gene that is only partially present, missing chromosomes or extra chromosomes. The human body likes the exact number of genes it is supposed to have and completely intact. If this is not the case, genetic abnormalities occur, which can lead to miscarriage or the birth of a human being with a congenital disease or defect.