Each one of us has a genetic blueprint — an ‘instruction manual’ that makes us uniquely human and determines our individual characteristics. This blueprint is contained in every cell of our bodies and is packaged into structures called chromosomes. Normally, there are 46 chromosomes — 23 are inherited from the mother and 23 are inherited from the father.
Chromosomal rearrangements refer to changes in the normal arrangement or size of a person’s chromosomes. People that have chromosomal rearrangements may not be affected – their chromosomes may be rearranged, but overall, they may still have a normal amount of genetic material. However, people with chromosomal rearrangements have an increased risk of creating an embryo with an incorrect amount of genetic material. In most circumstances, an incorrect amount of genetic material is incompatible with life. If these abnormal embryos are transferred, they fail to implant successfully or miscarry. However, some abnormal embryos can carry through to birth and result in a baby with a genetic disorder.
PGT-SR involves taking a biopsy of the embryo (5–7 cells from the outer layer) after it has grown and developed for 5–6 days. From this sample, we can analyse the genetic material of the embryo and determine whether a chromosomal rearrangement is present in the DNA or not. In this way, we can prevent the transfer of embryos that have a chromosomal rearrangement.
PDT-SR does carry some risks, including:
Embryos are fragile, so any procedure that involves handling the embryo and disturbing its surrounding conditions poses the risk of harm. However, while the risk of harm will always exist, it is thought that the overall risk of damage to the embryo is minimal.
When we conduct testing on a sample of cells from the embryo, we are assuming that this sample is representative of all the cells in the embryo. However, a condition called mosaicism may exist, where some of the embryo’s cells have the chromosomal rearrangement and some of the cells do not. Testing of embryos that display mosaicism can result in an inaccurate or unclear test result.
The results of the genetic testing may return as ‘indeterminant’, meaning the test could not determine whether the genetic material of the embryo was normal, or abnormal. This may occur for a variety of reasons, including a poor-quality embryo.
We may recommend PGT-SR if you or your partner carry a chromosomal rearrangement. We may also recommend PGT-SR if you have previously had a child or pregnancy affected by a chromosomal rearrangement.
Feasibility testing is also required prior to PGT-SR to see if your particular chromosomal rearrangement can be tested for. Your Newlife IVF fertility specialist will assess the specifics of your situation with you and make a recommendation accordingly.
At Newlife IVF, PGT currently costs $699 per embryo. Feasibility testing costs $1800.*
*Fees correct as of 1 August 2019.
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