Mart Diagnostics Early Pregnancy Monitoring
This is an arm of the brand responsible for early pregnancy diagnostics and monitoring. Through this Clinic, Sickle cell carrier couples can get a chance to screen their embryos before conception to avoid a sickle cell baby. Although this process is quite expensive, it compensates for the physical and emotional stress of dealing with sickle cell babies.
Our success in PGT with regards to the ability to diagnose improved significantly from 2010 when we did a day 3 biopsy (31% undiagnosed) to (9% undiagnosed) in 2014 when we changed to trophectoderm biopsy. Also, our pregnancy rate improved from 9% in 2010 to 50% in 2014, making us one of the best fertility clinics in Lagos. We now have ongoing pregnancy in 4 patients. Two of them have singleton babies while the other two have twins, and these babies are all sickle cell free.
WHAT IS PGD/PGT?
PGD is testing for specific genetic defects in the DNA code before embryo implantation. Usually, there is targeted testing of a known genetic abnormality in the couple. In recent times Preimplantation Genetic testing is used to describe all types of PGT. It was first performed in the early 1990s as a way for couples to prevent the pregnancy of a child with a genetic disease.
Here, at Medical Art Center, we offer PGT testing for genetic conditions, including sickle cell anemia and chromosome aneuploidies. We work in collaboration with Genesis Genetics, a world-renowned genetics institute. They pioneered PGT testing of embryos for inherited genetic abnormalities such as:
PGT-A: For aneuploidy testing to screen for chromosomal abnormalities in the embryos before they are implanted into the womb of the mother. It would ensure that normal babies are born. Abnormalities like Down syndrome that occur in advanced maternal age are eliminated with PGT-A.
PGT-M: A monogenetic disease for single gene disorders. It would help to ensure that Sickle cell carrier couples will not give birth to a baby with Sickle cell disease.
PGT-SR: Structural rearrangement for chromosomal deletion or translocation. It would prevent other abnormalities such as dwarfism, Turner’s syndrome, and more.
Applications OF PGT IN NIGERIA
•PGT-M (Monogenetic disorders). Autosomal dominant disorders: This is the situation where one partner is a carrier of the genetic defect (e.g., Dwarfism)
•Autosomal recessive disorders: This is a situation where couples are carriers of the genetic defect (e.g., Sickle Cell Disease)
•X-linked disorder( Disorder associated with the X chromosome of XX or XY): In this case, one partner is a carrier of an X-linked genetic defect (e.g., Hemophilia)
•Structural chromosomal abnormality: One partner is a carrier of a chromosome abnormality (translocation, inversion, deletion, insertion)
•Human leukocyte antigen (HLA) matching: Allogeneic hematopoietic stem cell transplantation (HSCT) is a treatment for some acquired and congenital diseases. An essential factor in the outcome is the degree of human leukocyte antigen (HLA) compatibility between patient and donor. The more compatible the donor is with the recipient, the higher the chances of success. HLA identical siblings, therefore, provide the best opportunity for the recipient. PGT can be used to select HLA-compatible embryos if there is no HLA-compatible sibling in the family.
PRELIMINARY Steps BEFORE PGT
Probe preparation
To go through PGT for sickle cell anemia, DNA samples from family members must be obtained to build the probe. However, samples from only direct family members are required, so there is no need to involve extended relatives. Usually, the siblings or the parents of the two partners are required. The probe built will be used to test the cells biopsied from the embryos. Traditional PGT probe preparation takes 14 to 16 weeks, while the newer Ultra PGT takes 8 to 10 weeks.
Oocyte Retrieval
The female partner is given medications to create multiple follicular development and ovulation. Once these follicles are well developed they are retrieved from the patient under conscious sedation using a special ultrasound-guided technique. The oocytes are then isolated from the follicles. The oocytes are allowed to rest in the incubator for about 3-4 hours before insemination. The time is used to prepare the sperm for IVF.
In Vitro fertilization (IVF)
In IVF, each isolated Oocyte is inseminated with approximately 3 drops of sperm solution from the male partner. It can also be fertilized by ICSI.
ICSI or Fertilization by “brute force”.
The technique was developed by Gianpiero Palermo at the Vrije Universiteit Brussel, in the Center for Reproductive Medicine headed by Paul Devroey and Andre Van Steirteghem in 1992. 14 In the USA the technique was developed by Jacques Cohen also in 1992. Prof. Oladapo Ashiru used this technique at the University of Illinois at Chicago in 1995. 16 Under a very specialized microscope one sperm cell is aspirated from the very few ones and is injected directly into the egg cytoplasm. This ensures fertilization in significantly high numbers.
The inseminated eggs are kept in the incubator in the IVF laboratory for about 3 days. The fertilized embryo will rapidly divide into the 2-cell, 4-cell, and 8-cell stages at which point about 1 or 2 good embryos are selected and transferred into the uterus through the cervix.
IVF is a good treatment option when the fallopian tubes are blocked or in endometriosis and where the male partner has a low sperm count.
Embryo Development
Several culture techniques have been developed to ensure that fertilization takes place in an IVF laboratory. Several gamete manipulations can be utilized for the fertilization process. They include embryo development to a blastocyst stage and cytoplasmic transfer.
DOES PGT REPLACE PRENATAL TESTING?
No, PGT does not replace prenatal testing, such as chorionic villus sampling (CVS) or amniocentesis. PGT is a research-based test allowing for a similar diagnosis to those available by prenatal testing. However, prenatal testing is still recommended as these widely used and well-accepted prenatal tests remain the gold standard of modern obstetrics and are necessary in this setting should a pregnancy ensue.
