Texas Fertility Center San Antonio

Preimplantation Genetic Diagnosis

Preimplantation genetic diagnosis can identify specific genetic disorders

TFC-San Antonio is committed to helping hopeful parents have healthy babies. One way our San Antonio fertility center achieves this goal is through the use of IVF and preimplantation genetic diagnosis, or PGD. PGD can help men and women with a known family history of genetic illness avoid passing the disorder to their children.

Preimplantation genetic diagnosis is more complex than preimplantation genetic screening

Although both preimplantation genetic screening (PGS) and preimplantation genetic diagnosis (PGD) test embryos prior to their transfer into the woman’s uterus, they evaluate different things.

  • PGS can identify if embryos have the correct number of chromosomes. This significantly reduces a couple’s risk of having a baby with a disease caused by an abnormal number of chromosomes, for example Down’s Syndrome, Turner’s Syndrome or other trisomies or monosomies. A trisomy (like Down’s syndrome) occurs when there is one extra chromosome – in this case an extra chromosome #21. A monosomy (such as Turner’s Syndrome) occurs when there is a missing chromosome – in this case a missing X chromosome.
  • PGD is much more advanced. It can determine if an embryo has or carries an abnormality in a specific gene. This allows for the detection of such disorders as cystic fibrosis, Tay Sachs, or sickle cell disease. PGD can also determine which embryos are unaffected by the disorder and would therefore result in the delivery of a healthy baby free of this condition.

Preconception genetic testing (“Carrier Screening”) can determine if you need PGD

The American Congress of Obstetrics and Gynecologists (ACOG) and the physicians at our San Antonio fertility center recommend preconception genetic testing or “carrier screening”, to all men and women who are thinking about having a child. The goal of testing is to identify if an individual or couple carries a genetic disorder that they could pass to their baby. Before screening, many hopeful parents have no idea that they, themselves, carry a genetic disorder.

Carrier screening is very simple; it only requires the male and female partner to provide a blood or saliva sample which is then evaluated by an outside genetics laboratory. Results are produced within a few days. Although most individuals are unaffected carriers of isolated genetic disorders, in order to have a baby affected by the disease, in most cases, both members of the couple must be carriers. Even then, their risk of having an affected child is only 1 in 4 (25%). Carrier screening allows us to identify couples who are “at high risk” of having an affected child so that we can then counsel them about their options. These options include IVF with PGD in order to avoid transferring an affected embryo, using donor sperm or donor eggs (to remove the possibility of the baby inheriting two abnormal genes), adoption, or pursuing pregnancy without testing – in the hope that their child will not be affected.

If you think that you could be a candidate for PGD, please contact us today. Our experienced and compassionate fertility specialists are here to answer all of your questions.