Between the processes of egg retrieval and embryo transfer, pre-implantation genetic testing (PGT-A) and pre-implantation genetic diagnostic for monogenetic diseases (PGT-M) are both performed during an IVF procedure. While these procedures have the same goal of allowing for the conception and birth of a healthy child, they are fundamentally separate laboratory processes.
PGT-A entails screening embryos to see if they have the correct number and location of chromosomes, whereas PGT-M is used when patients know they have or are carriers of a genetic condition such as sickle cell disease. The approach can distinguish between embryos that are affected by the illness and those that are not.
Humans are meant to have 23 pairs of chromosomes, with each chromosome inheriting one copy from each parent. However, aneuploidy occurs when embryos are created with too many or too few chromosomes. Aneuploid embryos may be born with disorders such as Down syndrome or Trisomy 21. In some circumstances, aneuploidy causes miscarriage.
PGT screens for aneuploidy, which is the presence of an abnormal number of chromosomes in an embryo, and is the most common cause of miscarriage and congenital anomalies, such as Down syndrome, Edwards syndrome, and Patau syndrome. It is also the most common cause of a first-trimester miscarriage.
PGT-A can identify euploid embryos, which have the normal number of chromosomes, and increase the likelihood of a successful pregnancy and a healthy baby.
This is possible by virtue of the fact that it can detect whether an embryo has the proper number of chromosomes to develop into a viable pregnancy and healthy infant. When a woman has numerous miscarriages or failed IVF cycles, she should explore PGT-A to see if chromosomal problems are to blame. Esther and George, a couple from one of the southern states in the country has tried to get pregnant. None of the previous therapies, such as ovulation induction, intrauterine insemination (IUI), and in vitro fertilization (IVF), worked. To boost their chances of delivering a healthy child, they opted to attempt PGT-A, which analyzes embryos for chromosomal abnormalities.
They had three cycles of IVF to pool embryos and ended up with eight blastocysts which were then biopsied and they ended up with four viable embryos (no chromosomal abnormalities). Two embryos were transferred in a frozen embryo transfer cycle and two weeks after transfer, they had a positive pregnancy test result followed by a transvaginal ultrasound scan (two weeks later) which showed a healthy heartbeat in the developing baby. They welcomed their son, Micheal who was born healthy and joyful nine months later.
Lara and Jaiye, an Edo state-based couple had a history of failed implantations. They had four IVF cycles, but none had worked. They met with a well-known Medical practitioner, who sent them to a well-known fertility clinic in the area, where they were introduced to PGT-A, to help boost their implantation rate and lower their chance of miscarriage.
The couple agreed to give it a shot, and they underwent their two rounds of IVF cycles with PGT-A, they biopsied and evaluated six embryos, four of which were euploid. They were overjoyed to find a positive pregnancy test and two heartbeats on the ultrasound after transferring two of the embryos to Lara’s uterus. They were having twins! They had a smooth pregnancy and delivery, and they gave birth to a healthy and lovely boy and girl. Lara and Jaiye were overjoyed.
Preconception genetic testing, which needs both the male and female partners to supply a blood or saliva sample, is the first step in the process of preimplantation genetic diagnosis for monogenetic illness (PGT-M). The material is then processed by a reference genetics laboratory. If testing shows that a couple is at danger of passing on a genetic problem, the genetics lab will either utilize a known probe or the pair’s genetic material to construct a genetic probe for a specific ailment. An embryologist will combine the probe with a few cells from the couple’s embryos after it is complete to detect which embryos are affected by the condition.
Bisi and Dapo are an Abuja couple. They have a hereditary condition that affects the nervous system and causes severe developmental delays and death in childhood. According to the physicians’ explanations, the couple had a 25 per cent possibility of producing a kid with the condition, and they did not want to accept that risk. They chose to undertake preimplantation genetic testing for monogenic diseases (PGT-M), which is able to discover the disease-causing gene mutation. They used PGT-M for IVF and had eight embryos examined.
The mutation had no effect on four of them, and two of them were put into Bisi’s uterus. They were overjoyed to discover a positive pregnancy test and a healthy heartbeat on the ultrasound.
With a significant family history of breast and ovarian cancer, it was a hardship for Anna and David from Lagos. Anna had a gene mutation, which raised her chances of developing these diseases. She also had a low ovarian reserve, which made spontaneous conception difficult for her. She wanted to have a child, but she also didn’t want to pass on the mutation to her children. She chose PGT-M, a test that looks for the mutation in embryos.
Anna underwent PGT-M IVF and had five embryos examined. Three of them tested negative for the mutation, and one was implanted in her uterus. On the scan, she saw a positive pregnancy test and a healthy heartbeat. She had a normal pregnancy and delivery, and she gave birth to a healthy boy who lacked the mutation. Anna and David were thrilled that their baby son was healthy.
Couples interested in PGT-M should speak with their doctor and a genetic counselor to understand the legal situation and clinical choices, and to make informed and responsible decisions.