By: Dr. Monika Chawla
Children whose parents are cousins run more than double the risk of being born with a congenital abnormality. These marriages are a strong tradition in the MENA region due to the cultural importance of higher familial compatibility and stability. However, it has its downsides.
Birth defects, also known as congenital abnormalities, can range from relatively minor problems such as extra fingers or toes through to major life-threatening disease such as holes in the heart or brain development disorders. Preimplantation genetic diagnosis (genetic diagnosis before pregnancy starts) helps in the identification of these diseased embryos before conception. It begins with the process of in vitro fertilization that involves taking eggs from a woman’s body and then fertilizing them in a laboratory. Over the next three days, the embryo divides into a cluster in the laboratory. One or two cells are removed from the embryo carefully in a biopsy. This causes no damage to the embryo and is done skillfully. The cells are then evaluated to determine if the inheritance of a problematic gene is present in the embryo. Once the PGD procedure has been performed and embryos free of genetic problems have been identified, the embryo are placed back in the uterus, and implantation is possible.
CASE REPORT #1
Mrs. FA attended the clinic one year ago with a history of two out of three children affected by “lysosomal storage disorder”, a rare and lethal disease that causes the accumulation of dangerous toxins due to a genetic enzyme defect. F told us that the children seemed absolutely healthy when they were born but gradually discovered they suffered from serious infections, diarrheas, and hernias. Later, there was deformation of facial features, an enlarged tongue and enlarged liver (hepatomegaly). Other signs of this disease are mental retardation and development delay. The parents’ lives had taken an unexpected, drastic turn and they searched desperately for solutions. The couple, who were married first cousins, were later diagnosed with a passive carrier gene which caused the emergence of this disease. This detection allowed an innovative, life saving preventative measure to be taken. F underwent a treatment called preimplantation genetic diagnosis (PGD), which allowed careful selection of healthy embryos for implantation, and has just delivered a healthy baby boy. Her joy has no bounds.
CASE REPORT #2
A and MJ were trying to conceive after three years of marriage. Both parents had heterozygous mutation (gene defect carriers) for Beta Thalassemia, which was a concern for their previous pregnancy. After undergoing hardships with their first child who did suffer from Beta Thalassemia disorder and needed repeated blood transfusions, they wanted to be cautious in their approach.
PGD provided a miraculous aid to healthy conception. The couple underwent In vitro fertilization and genetic testing for embryos not only for the thalassemia gene but also for the Human leukocyte antigen (HLA) tissue type. This test ensures that the new born child will be not only be born free of illness but also can function as a stem cell donor for treating the sick child. With aid of PGD, A conceived and recently underwent a caesarean delivery of an unaffected healthy baby. The umbilical cord blood of this baby was collected for treatment of the baby’s brother.
PGD of single gene disorders, combined with HLA matching, represents one of the most recent developments in reproductive medicine. This strategy has emerged as an excellent tool for couples at risk of transmitting a genetic disease. As discussed above, a great benefit of the technique is that it allows the selection of unaffected, compatible embryos that can function as stem cell donors for affected siblings.
At delivery, cells from the newborn’s umbilical cord blood are collected and used to reconstruct the blood system of the affected sibling, a lifesaving measure: the availability of a HLA-compatible donor raises the chance of cure to over 90%.
In a recent breakthrough at Fakih IVF, Abu Dhabi, PGD (preimplantation genetic diagnosis) has been used to identify rare cancer genes (BRCA-1 and 2) which lead to a 70-80 percent risk of breast cancer. Women have to undergo mutilating surgery for the removal of breasts at a young age to prevent cancer. This can be avoided by identifying the high risk gene in embryos and implanting only embryos with low cancer risk. Fakih IVF recently enabled one of five such PGD-undergone pregnancies, a remarkable milestone for reproductive health.
PGD is a great development in the field of IVF and helps to prevent the negative effects of consanguineous marriages, which makes it an especially useful tool in the MENA region. It is also useful for carriers of sex-linked genetic disorders or chromosomal disorders (for example Down’s syndrome), women aged 38 and older, women who experience recurring pregnancy loss and women with repeated failed fertility treatment. It’s a revolutionary development in science and is here to stay.