Everyone has special genetic traits that run in the family – grandma’s curly hair, dad’s green eyes, and mom’s slender wrists. These have nothing to do with a person’s health.
But sometimes, there are negative genetic traits that can be passed down. For some families, genetic abnormalities such as the breast cancer genes (BRCA1/BRCA2), Cystic Fibrosis and Spinal Muscular Atrophy can be passed down the family line.
Some 7.9 million children are born each year with a birth defect. For more than half of these defects, the cause is unknown.
Other families, though, have uncovered their genetic predispositions. If you are aware of genetic abnormalities in your family line, you may want to consider preimplantation genetic diagnosis, or PGD, as it is sometimes called. These predispositions can be screened for prior to attempting pregnancy, as well.
PGD refers to determining whether an embryo possesses a dominant gene or pair of recessive genes prior to implantation to the uterus.
Preimplantation genetic screening (PGS) can screen for chromosomal abnormalities like Down Syndrome, which may not run in families, but are increased in women who are older, who have had miscarriages, or those who have had an abnormal fetus or child.
So if you’re looking to start a family, what does this mean?
The decision to consider PGD is a personal one. Some have seen many relatives diagnosed with breast cancer and want to prevent their daughter from having the risk, while others have experienced recurrent miscarriage, a possible signal that the embryos may have genetic abnormalities due to extra or missing chromosomes.
As a woman’s age increases and the strength of her ovarian reserve declines, the prevalence of chromosomal disorders increases. When women turn 40, the odds of having a child with Down Syndrome is one in 100. (Men aren’t off the hook either – the incidence of sporadic single gene abnormalities including developmental disorders after 40 increases to a cumulative risk of 1 percent. Unfortunately these cannot be screened for without knowing what to look for.)
Keep in mind that birth defects and genetic disorders are uncommon. There are 130 million babies born each year, and the vast majority have no birth defect or abnormality. This is not meant to scare you, but rather empower you with the knowledge to make a decision that is best for you.
For those who want to stop a family genetic disorder in its tracks, PGD is a simple solution. Through preimplantation genetic diagnosis, scientists can carefully test embryos for a specific genetic disorder prior to transferring an embryo into the uterus.
What does this mean? All embryos are tested for the disease, and the healthiest embryos are then selected for possible transfer and resulting pregnancy. Patients can move forward knowing that they will not have a child who will be genetically predisposed to an abnormality or disorder.
For women who have experienced the heartbreak of recurrent miscarriage, doing PGS can strongly increase the chances of a successful pregnancy.
For one patient who elected to have a double mastectomy after learning about her genetic predisposition to cancer, it brought peace of mind.
Kristy had already had three children through IVF when her family decided to test for genetic disease. She was shocked to learn that her grandmother, father, aunt, brother, sister and herself all tested positive for the BRCA1 and BRCA2 genes.
Before having her fourth child, she chose to have her embryos genetically screened. Of the three embryos, one had the genes while the others did not. Kristy then had that healthy embryo transferred, and delivered a baby boy.
About the Author:
Dr. Edward Marut is the Medical Director of FertilityCenters of Illinois in Chicago. He is a graduate of the Yale University School of Medicine, and has been treating patients with infertility for 32 years.