Eliminating sickle cell disease using IVF and pre-implantation genetic diagnosis by Prof. Oladapo Ashiru
The world’s sickle cell anemia day is celebrated on the 19th of June every year, and it is indeed vital to celebrate the inspiration and the future of this aspect of Health care. In Nigeria, the foundation for sickle cell anemia usually organize seminar to mark the day. Our center participate at the foundation training of staff with a lecture on preimplantation genetic testing.
This day is set aside to create more awareness on Sickle Cell Disease (SCD), the treatments available, and also how to take care of sickle cell patients. As we all know, SCD is a group of disorders that affects hemoglobin, the molecule in red blood cells that delivers oxygen to cells throughout the body. SCD patients have a typical hemoglobin molecule called hemoglobin S, which distorts the original biconcave disc of the red blood cell to a sickle or crescent shape; these patients usually have episodes of pain (in the abdomen, chest or joints) and exhibit a range of severity.
Hence, sickle cell disease is an autosomal recessive disease. This article discusses the roles of IVF procedures in curing SCD.
How does IVF relate to SCD?
In vitro fertilization popularly known as IVF is an assisted reproductive technique that achieves fertilization by the retrieval of oocytes from the female, collection of sperm from the male and then combining them manually in a laboratory dish, through a series of the procedure. From the first success in 1978, there have been upgrades in IVF procedures and introduction of newer techniques like ICSI, PGT, PCR, among many others. The introduction of these procedures gave rise to the exploration of knowledge into the viability and quality of embryos both morphologically and genetically; one of such is the Pre genetic implantation testing as both a preventive and corrective procedure for SCD.
According to the World’s Health Organization (WHO), sickle cell disease is the most prevalent genetic disease in the African region. While 75% of patients with SCD live in sub-Saharan Africa, Nigeria alone accounts for more than 100,000 births each year. Individuals who have only one copy of the mutation are said to have sickle cell trait, these people are usually healthy but can transmit the disease to their children. It cannot but be overemphasized that sickle cell disease is fast becoming an African disease.
Nigeria experienced her first IVF success by our very own Prof Oladapo Ashiru and Prof Osato Giwa-Osagie in 1989 at the Lagos University Teaching Hospital, making it the first in Sub-Saharan Africa.
Since then, there has been a rise in the awareness of IVF among Nigerians as well as an increase in the number of fertility clinics in Nigeria; collectively working to solve the problems of infertility.
This acronym stands for Pre-genetic implantation testing defined as the technique used to identify genetic defects in embryos created through in vitro fertilization before it is transferred into the womb thereby drastically reducing births with genetic abnormalities, miscarriages caused by chromosomal abnormalities and possible implantation failures.
There are different forms of PGT, namely:
- PGT-M (Monogenic or single-gene disorders)
- PGT-A (Abnormal chromosomal number)
- PGT-SR (Structural Rearrangement)
However, our focus is on PGT-M, which is used in conjunction with IVF treatment to test an embryo for single-gene disorders; this treatment is essential for couples that have a history of genetic disorders. One significant use of PGT is the human leukocyte antigen matching (HLA), which has been very instrumental in the cure of sickle cell disease in affected patients.
What is the relationship between PGT and SCD?
One of the proven answers to the question above is PGT- HLA typing for HLA matching for “cord blood stem cell transplant.”
HLA matching is a way to tell how closely the tissue of one person matches the tissue of another person. It is the name of the histocompatibility complex in humans; it is an integral part of the immune system that contains several genes that encode cell-surface antigen present proteins and is controlled by genes located on chromosome 6.
PGT-HLA typing, on the other hand, is used to select the embryo of an HLA tissue type compatible with that of a child, most likely a sibling who requires a bone marrow transplant especially in medical conditions like leukemia, thalassemia, and sickle cell disease, Fanconi Anemia, amongst many others.
PGT-HLA typing has emerged as a tool for couples to select unaffected embryos of an HLA tissue type identical to that of an existing affected child.
Cord blood, otherwise known as umbilical cord blood, is the blood present in the umbilical cord, and it is an alternative source of hematopoietic progenitor stem cells. The first successful cord blood transplant was done in 1988 in a child with Fanconi Anaemia.
Since then, there have been advancements in the procedures for PGT-HLA typing, cord blood transplant conditioning, support system, and overall tissue engineering.
In the most basic terms, PGT-HLA typing is used to determine the embryo eligible for cord blood, which contains hematopoietic stem cells used for transplantation. The embryos with compatible HLA types called “savior child.” At their birth, the cord blood is collected and then stored for the present, or future use as the case may be.
In first PGT research published in the Nigerian Medical Journal by Ashiru et al., 2014 on the successful outcome of IVF following PGD/PCR screening for single gene disorders in 2012, it was discussed that PGD used for the detection of sickle cell anaemia is a powerful diagnostic tool for carrier couples who desire a healthy child but wish to avoid the difficult decision of whether to abort an affected fetus.
They have since then helped several couples to have sickle cell free babies. Our mission at Medical Art Center is to provide the state of the art technology in the management of infertility and other reproductive health problems.
Through PGT, we are continually providing solutions to couples that have a history or are carriers of single-gene disorder.