Archive for the ‘Array Comparative Genomic Hybridization (aCGH).’ tag
By Eva Schenkman, M.S., C.L.T., T.S.
November 26th, 2012 at 12:49 pm
Tagged with aCGH, Array Comparative Genomic Hybridization (aCGH)., Eva Schenkman, Free PGD, Free PGS, improved pregnancy rates, IVF Long island, IVF over 35, LI-IVF, Li-IVF Study, Long Island IVF, Long Island IVF PGD/PGS Study, PGD, PGD Study, PGS, PGS and live birth rates, PGS Study, preimplantation genetic screening, recurrent miscarriage, repeat miscarriage, repeated IVF failures, Reprogenetics, Reprogenetics PGD Study, Trying to Conceive
With advancing maternal age more embryos have chromosome abnormalities, from 60% in women younger than 35 to 80% in women 40 and older. This results in embryos failing to implant, pregnancy loss (miscarriage), or affected babies (i.e. Down’s syndrome). Because of that, more than one embryo is usually transferred during IVF. However, if two or more normal embryos implant, twins or triplets may result, which may result in a higher risk of congenital abnormalities, premature birth, and developmental problems.
A technique called PGD/PGS (preimplantation genetic diagnosis/screening) can detect if embryos are normal for chromosomes and may prevent the above problems.
In order to take advantage of this cutting edge technology, a woman must undergo in vitro fertilization (IVF), so her embryos may be examined. Embryos produced after IVF can be tested for the correct number of chromosomes through PGD/PGS. During this process, a biopsy is performed on embryos on day 3, 5 or 6 of development, by inserting a small needle and withdrawing a few cells. Preliminary studies have shown that the biopsy does not harm the subsequent development of the embryo.
The biopsied cells are sent to a genetics laboratory, Reprogenetics, for rapid PGD/PGS testing using array CGH, a technique that allows for the analysis of all chromosomes, while the embryos remain in the IVF laboratory. PGD results are available in less than 24 hours, and an embryo classified by PGD/PGS as normal, can be transferred back to the woman’s uterus the next day. Extra embryos can be cryopreserved for future attempts at pregnancy.
Most studies performed to date have shown an improvement in pregnancy outcome when PGD/PGS is performed using array CGH. Yet, so far, only one study (Yang et al. 2012*) has been performed with the utmost scientific rigor, that is, by blindly assigning patients at random to either a control group (no PGD) or to a PGD group.
This study was performed in young patients and showed that PGD significantly improved pregnancy rates even though only one embryo was transferred per woman. However, the same study has not yet been done for older patients (35 and older). In theory, older patients should benefit equally or more than younger ones since they produce more abnormal embryos.
We are excited to report that Long Island IVF has partnered with Reprogenetics and is currently recruiting patients for a study that will determine if this PGD approach is also beneficial for women 35 and older.
If you are eligible you will be randomly assigned to either a control group (regular IVF and no PGD) or to a PGD group. The cost for PGD will be free. If you are assigned to the control group, have a transfer as a study participant, and do not become pregnant you will be offered PGD for free in your next IVF cycle. Eligibility depends on several factors which are determined at various stages of the IVF process, including the age of the woman (35 or older), having normal ovarian reserve, and producing 3 or more blastocyst embryos by day 5 of development. The PGD group will have only one normal embryo transferred while the control group will have up to two untested embryos transferred.
For more information, including the study’s complete eligibility guidelines and medically-qualifying criteria, contact: Eva Schenkman, MS, CLT, TS Senior Embryologist at Long Island IVF at 631-881-5337 or email at Evas@longislandivf.com
*[Yang et al, Molecular Cytogenetics. 2012, 5:24]
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Does the potential of PDG to significantly improve pregnancy rates in older women make this technology something you’d consider using?
By David Kreiner MD
November 5th, 2012 at 10:08 pm
Tagged with abnormal embryos, aCGH, American Society for Reproductive Medicine, Aneuploidy, Array Comparative Genomic Hybridization (aCGH)., ASRM 2012, ASRM San Diego, biopsied embryos, blastocyst biopsies, blastocyst embryos, David Kreiner MD, euploid, Infertility Treatment, IVF, live birth rates in IVF, Long Island IVF, mosaicism in PGS, PGD, PGS, PGS and live birth rates, pre-embryo genetic screening, repeat implantation failures, repeat miscarriage, vitrification
Annually, reproductive endocrinologists and fertility experts from all over the world converge for information sharing and presentations of the most recent scientific advances in our field. This year, the American Society for Reproductive Medicine (ASRM) meeting took place in San Diego, in a venue that was fertile ground for the growth and development of reproductive medicine.
Among the most exciting topics was the use of pre-implantation genetic screening (PGS) of embryos to improve IVF live birth rates and eliminate miscarriages. Aneuploidy, the presence of chromosomally abnormal embryos, may be diagnosed through PGS with techniques that can analyze all 23 pairs of chromosomes. One such method, aCGH (microarray comparative genomic hybridization), is available in most labs on day 3 cleaved biopsies as well as blastocyst biopsies.
The biopsied embryos can be determined to be euploid (chromosomally normal) or aneuploid. Transfer then can be limited to only the euploid embryos which will eliminate most miscarriages and potentially improve the live birth rate. This is especially useful in cases of repeat miscarriages and repeat implantation failures.
Whether to have the embryos biopsied on day 3 or day 5 depends on a few factors:
1- Day 3 biopsy is a somewhat more invasive procedure with a higher rate of mosaicism (embryos containing multiple cell lines) leading to occasional false positive results.
2- Day 5 biopsies are less likely to lead to fresh transfers. Success is dependent on the survival of thawed frozen blastocysts. The recommended form of blastocyst freezing is through vitrification.
Since most miscarriages are the result of implanted aneuploid embryos, we hypothesize that if we add PGS to an IVF protocol we can prevent most miscarriages.
In one study where PGS was performed as an adjunct to IVF/ICSI for patients with recurrent miscarriages (>2miscarriages), it was found that 53.7% of embryos studied were aneuploid in patients with a mean age of 37.5. In 21.4% of all cases studied all the embryos from the IVF cycle were found to be aneuploid.
I recommend that you ask your physician whether PGS would be useful in your case.
By Dr. David Kreiner
March 1st, 2012 at 6:25 pm
Tagged with aCGH, aCGH vs. FISH, Array Comparative Genomic Hybridization (aCGH)., blastocyst testing, David Kreiner MD, Fertility, implantation failure, Infertility, infertility information, Infertility Treatment, Long Island IVF, Miscarriage, PGS, pre-embryo genetic screening, recurrent miscarriage, Single Embryo Transfer, TTC
Pre-embryo genetic screening (PGS) was developed to help weed out embryos containing inherited metabolic disorders and genetic abnormalities prior to implantation. It was thought that PGS could be used to minimize the risk of miscarriage and perhaps even increase live birth rates in older women IVF undergoing .
We have thus far been disappointed in our results obtained using the FISH technique, the procedure performed for PGS for the past decade and a half. But an alternative new technology that was recently developed makes me very excited about PGS once again: Array Comparative Genomic Hybridization (aCGH).
ACGH is a technique actually applied to detect deficiencies and excesses of genetic material in the chromosomes. DNA from a test sample and a normal reference sample are labeled using colored fluorophores that hybridize to several thousand probes. These probes are created from most of the known genes of the genome and placed on a glass slide.
The differential color of the test compared to the normal sample DNA reflects the amount of DNA in the test specimen. It can pick up monosomies, trisomies or significant deletions on an embryo’s chromosomes.
The first baby born from this procedure was in September 2009 to a 41-year old woman. When aCGH is performed on a Blastocyst biopsy, it is effective in screening out mosaicism (mixed cell lines in the same organism). ACGH is 20 percent more sensitive than the best FISH assays with an error rate of two to four percent. Fifty percent of the embryos tested were normal with pregnancy rates exceeding Blast transfers without aCGH screening.
So, who could benefit from using this newer technology?
1. Patients with repeat miscarriages can eliminate up to 90 percent of their miscarriages.
2. Older patients who naturally have a higher percentage of genetically abnormal embryos may now screen for and only transfer their normal embryos.
3. Patients who want to maximize their success with a single embryo transfer.
4. Patients who have experienced repeat implantation failure can be screened for genetically abnormal embryos.
This technology is available for about the same cost as the FISH procedure yet, since it is performed on a Blastocyst, it is safer with less effect on the integrity of the embryo and without significant risk of wrongly identifying abnormal embryos. A concern with FISH is that embryos identified as abnormal can actually result in a normal fetus. This risk is practically eliminated with aCGH and is another reason making it more successful.
I expect PGS will now become a commonly used addition to standard IVF to promote more successful single embryo transfer, improve success in older patients, eliminate miscarriages and treat patients with repeat implantation failure.
We are approaching a new era in IVF. Brace yourselves for a thrilling ride into IVF’s future.