In this session, Roy Pascal Naja, PhD, DipRCPath, Laboratory Director at IGENOMIX UK, who has talked about the role of genetics in female & male reproduction.
In repetitive implantation failure or miscarriage cases, patients should undergo genetic testing, and the clinician will ask for a Karyotype test regardless of age.
If you’re seeking donor eggs and you’re at an advanced maternal age, the clinician might not ask for any genetic testing from you. Depending on the donor’s age, if it’s a young donor, the probability is that those eggs are going to be good, there’s not going to be gains and losses of chromosomes, and you might not need genetic testing.
At the moment, I don’t think this is going to be common practice because the technique is very invasive and it’s very costly. However, in the future, there’s a lot of research where scientists are looking into creating eggs from something we call the stem cell, so from your skin. If you take a piece of your skin, you can produce eggs in a lab, and then you can fertilize this egg in a laboratory, you don’t need to stimulate the patient, so give the patient a lot of hormones to produce a lot of eggs, and it’s an invasive process, you go in with the catheter to collect these eggs.
All of this could be scrapped if we could create eggs from stem cells and then fertilize these eggs in a laboratory, and then you can just test these embryos, why not, and you’ll be able to test for many things in the future. I see it happening in the future if this stem cell technology is perfected. At the moment, not because this is a very invasive and costly procedure.
No genetic testing is not harmful to the embryo. What could sometimes be harmful to the embryo is the biopsy. However, many IVF clinics are very good and have experienced biologists that have perfected biopsying embryos, most times it will not cause any harm to the embryo.
This test usually looks at the genes expressed in your endometrium, our test is the most common test available in the market. We look at 236 genes that have to be expressed in a certain way to make your endometrium receptive. You do this test in a natural cycle, the clinician takes a piece of the endometrium and puts it in a tube, and we do the genetic testing. This is done in your luteal phase or after your LH surge, or in a slightly medicated cycle.
Then we’ll test this in this endometrium or this piece of the endometrium, and it’s not a harmful process. You get local anaesthesia, and we’ll let you know if this endometrium is receptive, so if your window of receptivity is where it’s supposed to be, which is at day 19, and we’ll also tell you if your endometrium has the good bacteria to accommodate the embryo.
At Igenomix, we’ve developed a test called non-invasive PGS or PGT-A (non-invasive Pre-implantation Genetic Screening (NI-PGS) where we don’t biopsy the embryo, we just take some droplets where your embryo is growing because the embryo is spitting out cells, and these cells will show 80% of the time if the embryo has gained chromosomes or lost chromosomes. It’s a non-invasive technique, we’ve just launched it last year, and it’s an alternative option for PGS.
Nowadays, we use something called next-generation sequencing (NGS), you’re doing PGT-A and NGS, or next-generation sequencing is very sensitive, it can pick up mosaicism. We found (this is internal data) that only 5% of the time the embryo is mosaic, meaning we’re not sure if the embryo has an abnormality or not, only 2.8% of the time, this embryo will have a low level of mosaicism.
This embryo is given a chance to be transferred, but before transferring this embryo, the patient will undergo genetic counselling where the genetic counsellor will explain the risks of transferring a low mosaic embryo, but that’s only 2.8% of the times.
It’s different, it’s not diagnostic, it’s a test that gives priority to the embryo, so if you have 4 embryos produced in an IVF cycle, and we do this non-invasive PGS, it will give you the answer on which embryo is best. For example, embryo number 4 is the best, embryo number 2 is the second-best and so on.
It gives a chance for every embryo to be transferred, so that’s its advantage over PGS, but it’s only 80% sensitive compared to PGS. PGS will give a more precise answer to whether you have lost or gained a chromosome. There’s pros and cons for non-invasive PGS.
It’s important to understand the difference between choosing what ended up from the parents into the embryo. For example, if mom has a genetic disorder, mom has a 50% chance of passing this genetic disorder to the embryo.
When you do PGT or the pre-implantation genetic testing, you screen for the good gene of mom, which 50% of the time statistically is passed onto the embryo. We’re just looking at what ended up in the embryo, and we’re not changing anything in the genetic makeup, so if you’ve heard of gene editing, then it’s actively changing your genetic material, and then you’ll have designer babies, but with PGT there are no designer babies.
Certain studies suggest some patients with some gene defects are more prone to develop fibroids, but usually, these fibroids are not caused by genetic issues. Once they’re removed, they should not cause any infertility leiomyomas.
Sometimes a very bad lifestyle, lots of smoking and drinking alcohol will lead the DNA to fragment in the sperm. There are certain cases where the clinician will ask for a DNA fragmentation test to see if it’s elevated as compared to a normal person.
Some studies associate a high DNA fragmentation with chromosomal abnormalities in embryos. The clinician will ask you about your lifestyle and diet, and sometimes they will ask for DNA fragmentation to be done.