The Role of IVF & Genetic Testing
In addition to working with patients who carry sickle cell trait, fertility clinics can also work with patients directly affected by sickle cell disease. Thanks to advancements in the field of fertility treatment and genetic testing, those who carry sickle cell trait or have the disease are now able to avoid passing on the condition to their children.
Phase 1: IVF Treatment
IVF involves taking medications to stimulate the growth of eggs in the ovaries. After the eggs have matured, they are retrieved and fertilized with the patient's designated sperm (either from their partner or a donor).
Phase 2: Embryo Development & Biopsy
Embryos are monitored as they grow in the IVF laboratory until they reach the blastocyst stage, which is typically around Day 5 or Day 6. A small sampling of cells is carefully removed from the embryo(s) and sent to an external genetics laboratory for analysis.
Phase 3: Embryo Testing
The analysis of the embryo is known as preimplantation genetic testing (PGT) or, more specifically, preimplantation genetic testing for monogenic disorders (PGT-M).
To accomplish this, the lab would need samples from the couple (and usually other family members as well), to help track the chromosome carrying the mutation in the family. The genetics lab will then typically develop 'probes,' which are small stretches of DNA that match the familial mutation.
It can take several weeks to prepare for cases like these. These unique probes, as well as assessing other gene markers in the embryos, help to determine whether the embryos are positive or negative for the condition.
Couples pursuing PGT for sickle cell would typically also have their embryos analyzed for chromosome issues at the same time (PGT-A).
Phase 4: Results & Next Steps
As soon as your fertility clinic receives the results report from the genetics lab, they will know which embryos have chromosome issues, which embryos are affected with sickle cell, which embryos are carriers, and which embryos do not carry the gene.
Why Screening Both Partners is So Important
Some people with the condition have one copy of sickle cell trait, and a different type of mutation in their other beta-globin gene, such as hemoglobin C trait, or beta-thalassemia trait. So, if one person has sickle cell trait, it is crucial to test a partner for sickle cell trait as well as other possible beta-globin changes.
What causes sickle cell disease?
Sickle cell disease affects hemoglobin, which is the protein in red blood cells that carries oxygen to different parts of the body. Our adult hemoglobin is usually made of alpha-globin and beta-globin.
Red blood cells are usually round, but with SCD, they can be distorted into a sickle, or crescent shape. When the blood cells are sickled, they break down earlier than normal, leading to anemia.
Symptoms of Sickle Cell Disease
In addition to anemia, associated issues include recurrent infections, shortness of breath, chronic fatigue, and jaundice (yellowing of skin or eyes). The sickled cells can also get stuck in small blood vessels, leading to extreme pain, and even a loss of oxygen to different parts of the body, including the lungs, kidney, and spleen.
High blood pressure can be seen in blood vessels going to the lungs, which can be a severe complication. Children with sickle cell disease can also have delayed growth and many different complications. People with the condition need a lot of medical care to manage and control all of the related symptoms.
How long do people with sickle cell disease live?
The average life expectancy of those with sickle cell disease has improved since all children are now screened for the condition. However, life expectancy is still only in the mid-40s. Our ability to treat the condition has improved over time, allowing more people with the condition to live longer lives.
Treatment for Sickle Cell Disease
Like all patients with chronic disease, patients with sickle cell disease are best managed through a comprehensive, multidisciplinary care approach. Here's what you should know.
Health maintenance for patients with sickle cell disease starts with early diagnosis, preferably soon after birth. Treatments include penicillin prophylaxis, vaccination against pneumococcus bacteria, and folic acid supplementation.
General Treatment & Support
Treatments for sickle cell disease complications often include antibiotics, pain management, intravenous fluids, blood transfusion, and surgery. Establishing a strong psychosocial support system is also of the utmost importance.
Helpful resources include the Sickle Cell Disease Association of America, Centers for Disease Control & Prevention, SCDAA Sickle Cell Disease Educational Information Repository, and the American Society of Hematology.
Blood transfusions can help by reducing recurrent pain crises, risk of stroke, and other complications. Because red blood cells contain iron, and there is no natural way for the body to eliminate it, patients who receive repeated blood transfusions can accumulate iron in the body until it reaches toxic levels.
It is important to remove excess iron from the body, because it can gather in the heart, liver, and other organs and may lead to serious organ damage and even death. This is referred to as transfusional iron overload, and requires additional treatment.
A single randomized clinical trial of 299 patients with SCD demonstrated that compared to placebo, hydroxyurea was associated with lower annual rates of pain crises, painful episodes of acute chest syndrome and need for transfusions.
Bone Marrow Transplant
Bone marrow stem cell transplants have also been utilized for the treatment of sickle cell disease. As this procedure can impact future fertility, it is recommended that patients consider fertility preservation, including possible freezing of eggs, sperm, or embryos, before the transplant.
Treatment Options for Children with Sickle Cell Disease
Children usually take antibiotics as a preventive measure, since recurrent infections are a common problem. In some cases, a bone marrow transplant can be performed, but this procedure can be quite risky, and some of the medications needed for this type of treatment can have adverse side effects.
Be Aware & Proactive
Genetic screening for the sickle cell trait is crucial. While some people are aware that they have a family history of sickle cell disease, or have been tested previously, many don't even know that they are carriers.
Since many people carrying the sickle cell trait have no apparent health issues, it isn't uncommon for the disease to go unnoticed. If you are Black or Hispanic-American, it is important to undergo genetic screening before pregnancy so all available reproductive options can be considered.
With awareness, education, and proper screening, carriers of the sickle cell trait can still become parents - without the fear of passing on the disease to their future children.