Expert answers – what’s the difference between PGS and PGD?
Our Las Vegas IVF center offers two different types of genetic tests for embryos – preimplantation genetic screening, or PGS, and preimplantation genetic diagnosis, or PGD. Both types of genetic testing screen out abnormal embryos so only those that are “normal” can be transferred to your uterus. But, as our Las Vegas IVF experts explain, there is a big difference between PGS and PGD.
The difference between PGS and PGD is chromosomes vs. genes
When you elect to do PGS or PGD, cells are removed from each embryo created at our Las Vegas IVF center. These cells are then sent to a specialized genetics laboratory for analysis, and your embryos are frozen and stored at our laboratory while you wait for the results.
In PGS, the geneticists examine each cell’s chromosomes to determine if there are too many or too few – a condition called aneuploidy. When an embryo’s chromosomes are aneuploid, a pregnancy could end in miscarriage or cause the baby to have birth defects or intellectual disabilities, as with Down syndrome or Trisomy 13. If an embryo’s chromosomes are abnormal, that embryo can be set aside so that you can transfer an embryo that has a normal number of chromosomes.
So what’s the big difference between PGS and PGD? PGD goes deeper than PGS to analyze specific genes in the cell’s DNA, looking for the one that is linked to a known genetic disease. For example, if you know that cystic fibrosis runs in your family, the geneticists will search for the gene that is known to be linked to cystic fibrosis. If they find it, that embryo will be disqualified for transfer.
Geneticists can use PGD to search for more than 1,000 heritable diseases, including many common disorders that can cause lifelong disabilities or medical issues.
- Tay Sachs disease
- Spinal muscular atrophy
- Duchenne muscular dystrophy
- Huntington’s disease
- Sickle cell disease
Explore your genetic testing options
For most people with no family history of genetic diseases, PGS is enough to provide peace of mind before transferring embryos. However, if you or your partner has a family history of genetic disease, or if your genetic carrier screening indicates that one or both of you is a carrier of a genetic disorder, ask your Las Vegas IVF physician to determine if PGD could reduce your risk of passing a heritable disease to your children.
To learn more about the difference between PGS and PGD, contact us to schedule a consultation at our Las Vegas IVF center.