Embryo Genetic Screening – PGS / CCS
With the process of In Vitro Fertilization (IVF) we can fertilize the egg with sperm and produce embryos. The embryos are cultured in the laboratory for 5-6 days as they develop into the blastocyst stage and an embryo biopsy is than performed. The embryologist performs an embryo biopsy using a laser under control of the inverted microscope. At AFCT the embryo biopsy is performed personally by Dr. Dmitri Dozortsev, who was one of the pioneers of this technique at Reproductive Genetics Institute in Chicago. He prepares a set of custom made micro tools for each embryo biopsy to maximize its safety and effectiveness. The embryo biopsy is sent for testing by a courier, while embryos are frozen awaiting for the results from the test.
Studies have shown that close to 50% of embryos even from the best patients can be abnormal. The proportion of abnormal embryos increases with woman’s age usually after the age of 35 and a more dramatic increase in abnormality after the age of 40.
The vast majority of chromosomal errors are so-called de novo random errors, and the patient has no predisposition to any particular type of error or family genetic transmission. The visual appearance of chromosomally abnormal embryos will appear completely normal to an embryologist but will fail to implant, end up in a miscarriage or develop a child with chromosomal abnormalities.
Mosaic embryos are embryos that contain both normal and abnormal cells. When an embryo biopsy is made it is possible to obtain a biopsy that contains abnormal cells. The results will than reveal an abnormal embryo up to 20% of the time. This means that the embryo could actually lead to a normal pregnancy but the biopsy reveals an abnormal embryo. The mosaicism phenomena will eliminate several embryos that could result in a normal pregnancy but with an abnormal results, we will be reluctant to transfer that embryo to our patient. The problem becomes a major factor in patients who do not produce several embryos and particularly women older than 37 with fewer than 6 blastocyst. If we end up eliminating 20% of embryos, there are times when we will not have any normal embryos to transfer.
Embryo Biopsy with Complete Chromosomal Testing (CCS)
Preimplantation Genetics Screening (PGS), also known as Comprehensive Chromosomal Screening (CCS) is used to test all 46 chromosomes. Not all patients are good candidate for PGS. We prefer to offer PGS to patients with 6 or more embryos so that we can have at least 1-2 normal embryos to transfer.
This test is intended to rule out the risks of Down’s Syndrome and other common genetic abnormalities that increase with age greater than 35. Unfortunately, the individuals who we really want to have this test done usually have few embryos and may end up with an IVF cycle without any normal embryos to transfer.
In order to determine whether PGS is a good choice for you, please schedule a consultation. You will be able to meet with both, Dr. Allon and Dr. Dozortsev to discuss your particular circumstance.
Preimplantation Genetic Diagnosis – PGD
Genetic disorders like Cystic Fibrosis, Huntington Disease or so-called balanced translocations are family inherited. The majority of these genetic disorders are transmitted as an autosomal recessive fashion. This means that both male and female partner must carry the gene mutation in order to transmit it to their offspring. Unfortunately, the individual will not know if he or she are carrier of the mutation until they have a child with the two defective copies of that gene.
The good news is that testing of prospective parents for silent defective genes is now readily available, relatively inexpensive and in many cases is covered by health insurance. AFCT has partnered with a genetic testing company, which will provide PGD testing free of charge if both you and your partner carry the same copy of the defective gene.
The PGD Process – The PGD testing usually begins by having an evaluation by a genetic counselor and followed by obtaining a swab from your cheek and other family members in order to build a personalized DNA map. This process may take 4-12 weeks. Just like PGS, PGD requires In Vitro fertilization (IVF) and an embryo biopsy followed by embryos freezing.
If you are planning a family and wish to have genetic testing, please consult with your physician.
You may find numerous online recommendations of different methods of selecting a particular gender, but embryo screening prior to implantation is the only proven method with near 100% accuracy.
About 50% of the couples would like to select the gender of their child either for family balancing or other reasons. Couples without a known infertility etiology may also choose to do gender selection at AFCT. The chromosomal gender testing is also part of the Preimplantation Genetic testing (PGS).
Gender selection on frozen embryos
It is not uncommon that a couple ends up with several frozen embryos in storage after an IVF cycle and then decide to select the gender for future pregnancy.
At AFCT we are confident in high percentage survival (>90%) of embryos previously cryopreserved. Those embryos can be thawed out tested for the desired gender and vitrified again or transferred back into the uterus.
If you elect to do gender selection and you have embryos stored at another facility, you may transfer the embryos to our center and gender selection testing can be performed.
The Advanced Fertility Center of Texas (AFCT) has several fertility treatment centers located throughout the Houston metropolitan area. We offer the most comprehensive, state-of-the-art fertility services.