What are the Limitations and Risks of PGD?
- Pre-implantation genetic diagnosis can only test for 11 out the 23 pairs of chromosomes. Abnormalities in the remaining 12 chromosomes cannot be detected.
- The error rate for PGD in detecting an abnormal number of chromosomes is currently 10%.
- PGD cannot detect genetic mosaicism. That’s when genetic abnormalities may be present in one cell of the embryo, not in another.
- It is possible that none of the embryos will be found to be “normal”, but, because of the limitations described above, they may, indeed, be normal.
- For chromosomal translocations, PGD cannot detect abnormalities in chromosomes other than the one known to be involved in the translocation.
What are the Risks?
At present, the risks associated with embryo biopsy are unknown. Although a rare occurrence, it is possible to accidentally damage the embryo during biopsy that would result in developmental arrest. Embryo biopsy delays cell division by a few hours and some embryos fail to recover from biopsy. Embryo biopsy and/or genetic analysis may fail due to technical problems. It is simply impossible to know the relative benefits for any individual case.
Pre-implantation genetic diagnosis (PGD) is offered at our New Jersey practice because there are some cases in which it can be beneficial. However, it is expensive and at best can only detect abnormal numbers of 11 of the 23 pairs of chromosomes and, in some cases, a specific abnormality in the structure of a single chromosome. Moreover, PGD has a significant margin of error. PGD has been hyped and has led to unrealistic patient expectations (i.e. only PGD can give you a “normal” baby). PGD only scratches the surface of the potential genetic problems of the embryo. Genetic problems that cause embryos to stop growing after implantation are, by and large, undetectable by PGD. However, new technologies are being developed that may provide more accuracy and more detailed analysis of the embryonic genome.
If you would like to know more about this procedure or are wondering if pre-implantation genetic diagnosis (PGD) is for you, contact our New Jersey fertility specialist today. We will be happy to schedule a consultation for you.