Congenital Disorders of Red Blood Cells | NeoReviews | American Academy of Pediatrics
Sickle Cell Anemia: How It Is Diagnosed And Test Results
Doctors may carry out blood tests, prenatal screenings, and various other tests to assess a person's symptoms and diagnose sickle cell anemia.
Sickle cell anemia is a blood disorder that affects hemoglobin, one of the components of red blood cells. It is an inherited disorder, meaning an individual is born with it. It is the most common disorder in a wider group of health conditions called sickle cell disease (SCD).
It particularly affects individuals of African, Mediterranean, Middle Eastern, Hispanic, and South Asian descent. Timely diagnosis is crucial for effective management and to prevent serious complications associated with the disease.
In this article, we discuss how a doctor diagnoses sickle cell anemia, including what the tests might show if the person has the condition.
Diagnosing sickle cell anemia typically begins with a thorough medical history review and physical exam. Healthcare professionals will usually ask a person about their symptoms to look for signs of disease.
Some signs of sickle cell anemia include:
Sickle cell anemia symptoms
The symptoms may vary from person to person and can change over time.
Blood tests play a crucial role in confirming the diagnosis of sickle cell anemia.
Doctors may also order a peripheral blood smear test to examine the shape and size of red blood cells under a microscope. In sickle cell anemia, the blood smear reveals the presence of sickle-shaped or "C-shaped" red blood cells.
Doctors usually detect sickle cell anemia during pregnancy or soon after birth. Prenatal screening tests can identify the presence of sickle cell trait or sickle cell disease during pregnancy.
One common method is using a sample of amniotic fluid, which is the liquid in the sac surrounding a growing embryo. Another approach is chorionic villus sampling (CVS), which involves using tissue taken from the placenta.
Testing before birth can be done as early as 8–10 weeks into the pregnancy. Doctors look for the sickle hemoglobin gene rather than the atypical hemoglobin itself. However, this testing cannot predict the severity of the disease.
Prenatal genetic testing allows parents to make informed decisions about managing the pregnancy and potential risks to the baby.
In the United States, screening newborns includes a simple pinprick blood test to assess for sickle cell disease and sickle cell trait. Still, most newborns may not have symptoms until they are about 5–6 months old.
Genetic testing is common for diagnosing sickle cell anemia. It involves analyzing a blood sample to identify specific mutations in the sickle hemoglobin gene, also known as the HBB gene.
It can help determine which type of sickle cell disease a person has or can confirm a diagnosis when results from blood tests are not clear.
Genetic testing can assess whether a person has one or two copies of the sickle hemoglobin gene, as well as the inheritance pattern and risk of passing the condition on to future generations.
If both parents have the sickle cell trait (SCT), there is a 50% chance any child of theirs will also have the SCT. However, the parents may not have symptoms of sickle cell anemia, meaning they are carriers. However, carriers can still pass the SCT on to their children.
In addition to blood and genetic tests, healthcare professionals may recommend other diagnostic tests to evaluate the extent of organ damage and complications that may occur with sickle cell anemia.
These may include imaging and urine tests.
Doctors diagnose sickle cell anemia using a comprehensive approach that includes a medical history review, physical exam, blood tests, prenatal screening, genetic testing, and other diagnostic procedures. Early detection is essential for implementing appropriate management strategies and minimizing the risk of complications.
With advances in medical technology and increased awareness, the outlook for individuals living with sickle cell anemia continues to improve, offering hope for better quality of life and outcomes.
What Type Of Genetic Mutation Causes Sickle Cell Anemia?
Sickle cell disease (SCD) is a group of hereditary red blood cell disorders. Sickle cell anemia is a type of SCD that occurs when a person inherits genes containing an atypical form of hemoglobin.
SCD is the most common genetic disorder in the world and affects approximately 100,000 people in the United States. It is more common in those from certain ethnic groups, including African Americans.
Sickle cell anemia is typically the most severe form of SCD. When a person has sickle cell anemia, an atypical form of hemoglobin causes their red blood cells to become hard, sticky, and "C" or sickle-shaped.
These cells die earlier than usual, which causes a constant shortage of red blood cells. Additionally, the cells can get stuck in smaller blood vessels and block the flow of blood. This may cause pain and lead to other serious health complications, including a stroke, infection, and acute chest syndrome.
This article discusses the genetic mutation that causes sickle cell anemia, who is most at risk of developing the condition, and when a person needs to contact a doctor.
Sickle cell anemia occurs when a person inherits a gene from both biological parents that has a mutation that causes sickle-shaped red blood cells to form. Healthcare professionals call this gene the hemoglobin-Beta (HBB) gene. It is responsible for making hemoglobin, the protein that carries oxygen within the red blood cells.
A typical HBB gene produces red blood cells with hemoglobin-A. These cells are smooth, round, and able to pass through the blood vessels with ease.
When a person has sickle cell anemia, they inherit two HBB genes — one from each biological parent — that have a mutation that codes for hemoglobin-S instead. Red blood cells that contain hemoglobin-S are hard and sickle-shaped. These cells can build up and block the blood vessels, causing damage to vital tissue and organs.
If both biological parents carry the HBB gene with the mutation that produces hemoglobin-S, there is a 25% risk that each child they have will be born with sickle cell anemia. This is because a person needs to inherit two HBB genes with the mutation that produces hemoglobin-S to develop sickle cell anemia.
If a person inherits one HBB gene with the mutation that produces hemoglobin-S and one typical HBB gene that produces hemoglobin-A, there is a 50% risk that they will carry the sickle cell trait (SCT).
People with SCT do not usually develop symptoms of SCD, but in rare cases, they may develop health problems. Additionally, if someone with SCT has children, they may also inherit the HBB gene with the mutation that produces hemoglobin-S.
SCD is more prevalent among certain ethnic groups. Approximately 1 in 13 Black or African American children inherit one sickle cell gene from their parents, meaning they have SCT. Approximately 1 in 365 Black or African American children are born with SCD.
People from Hispanic American, Southern European, Middle Eastern, or Asian Indian backgrounds may also be more at risk of developing SCD.
Health disparities
A person with SCD may experience health disparities, which the Centers for Disease Control and Prevention (CDC) Foundation define as worse health outcomes in comparison with other diseases and access to fewer health resources.
These health disparities may include:
In some cases, someone with SCD may find it beneficial to reach out to a social worker or case manager to help them self-advocate and gain access to appropriate treatment.
Sickle cell anemia is the most severe form of SCD. It occurs when a person inherits a hemoglobin-Beta gene with a mutation that codes for hemoglobin-S from each of their parents.
Red blood cells containing hemoglobin-S are hard and resemble the shape of a sickle. These cells can build up and cause blockages in the blood vessels, causing pain and serious health complications.
SCD disproportionately affects people who identify as Black or have African ancestry. It may also affect people from Hispanic American, Southern European, Middle Eastern, or Asian Indian backgrounds.
A person can speak with a doctor for advice about how to manage their condition. If someone with SCD experiences a sudden onset of symptoms, such as a high fever, chest pain, or difficulty breathing, they should call 911 immediately.
A Possible Cure For Sickle Cell? - ScienceDaily
Sickle cell anemia is an inherited blood disorder where red blood cells become sickle/crescent shaped. It causes frequent infections, swelling in the hands and legs, pain, severe tiredness and delayed growth or puberty. Treatment typically focuses on controlling symptoms and may include pain medicines during crises; hydroxyurea to reduce the number of pain episodes; antibiotics and vaccines to prevent bacterial infections and blood transfusions.
While a remedy for this severe disease has remained elusive, a recent study in the New England Journal of Medicine (Biologic and Clinical Efficacy of LentiGlobin for Sickle Cell Disease/Kanter et. Al.), if proven applicable, may be a possible cure.
In an editorial in this week's New England Journal of Medicine, Martin Steinberg, MD, professor of medicine at Boston University School of Medicine, comments on the results of the study which was the first successful gene therapy for sickle cell disease that adds a gene to patient blood stem cells that prevents complications of sickle cell disease. "Gene therapy with autologous stem cells extends the possibility of a cure to all patients without the need for immunosuppression," explains Steinberg who also is hematologist at Boston Medical Center.
While patients in the study no longer had symptoms of sickle cell disease, Steinberg points out that most continued to have a shorter than normal lifespan of their red blood cells which he thinks could be associated with some complications in the longer-term.
Steinberg believes that for patients to accept this difficult and very expensive treatment it must be curative or nearly curative and last a lifetime. "At this point we do not yet know the sustainability of the results but based on this study the prospects seem good," he says.
Steinberg acknowledges that any highly effective gene therapy will not improve the health of most people with sickle cell disease throughout the world. "Most patients with this disease live in Africa and India where access to highly technological health care is limited. What is needed are more drugs that can be taken orally and increase fetal hemoglobin levels. This will have a higher likelihood of benefiting populations suffering the most from this disease."
This editorial appears online in the New England Journal of Medicine.
Comments
Post a Comment