Inheritance and Diagnosis of Sickle Cell Anemia
Disclaimer: Not medical or professional advice. Always seek the advice of your physician.
Sickle cell anemia is an inherited disorder that changes the shape of the red blood cell (erythrocyte) to look like a sickle due to a mutation in hemoglobin.
The sickle-shaped cells become more fragile and get stuck in small vessels, disrupting the delivery of oxygen to tissues and organs. As a consequence, people diagnosed with SCA develop problems with blood flow and other symptoms of the disease.
Who is at Risk for Sickle Cell Anemia?
A mutation in hemoglobin may occur if a child receives two sickle cell genes — one from each parent. This usually happens when both parents are carriers of the defective gene, or when one parent has sickle cell anemia and the other is a carrier of it. If both parents are carriers of the sickle cell gene, genetic traits can be passed in different ways.
- 1 in 4 chance that each child they have will not inherit sickle cell genes, will not have sickle cell anemia or be able to pass it on.
- 1 in 2 chance that each child they have will inherit a copy of the sickle cell gene from 1 parent and become a carrier.
- 1 in 4 chance that each child they have will inherit copies of the sickle cell gene from both parents and will be born with the disease.
Sickle cell anemia can affect anyone regardless of gender and race, but it is most common among African Americans. However, the disease has a protective effect against malaria.
Diagnosis of Sickle Cell Anemia
Prenatal Screening
Doctors recommend carrying out screening for sickle cells before 10 weeks of pregnancy so that future parents have time to consider further tests to determine the risk of having a child with this disorder.
Testing for sickle cell anemia during pregnancy involves the collection of fetal DNA using a chorionic villus biopsy or sample of the amniotic fluid surrounding the fetus.
Newborn Screening
Each state in the United States requires universal newborn screening for sickle cell anemia.
The test is based on the analysis of blood samples collected from the infant's heel. This method helps identify the presence or absence of SCA and the chances of a child inheriting sickle cell trait. If an infant has a positive newborn screening result for sickle cell anemia, an additional blood test is usually performed to confirm the diagnosis.
Blood Test for SCA in Children and Adults
Sickle-shaped red blood cells can be seen in a blood sample examined under a microscope. However, the diagnosis of sickle cell anemia requires a special blood test called hemoglobin electrophoresis. The test measures the exact amount of abnormal type of hemoglobin. Depending on the percentage of sickle hemoglobin, it can be determined whether a person carries the sickle cell gene or has sickle cell anemia.
Other options include rapid screening tests that help identify sickled erythrocytes by removing oxygen. These tests are rarely used as they cannot differentiate between sickle cell anemia and sickle cell trait (when a person is a carrier of the gene for sickle cell anemia without being sick).
Sickle cell anemia cannot be completely cured. However, patients can increase their life expectancy and avoid complications if they follow all medical recommendations.
It is also impossible to prevent the development of SCA since the disease is caused by a genetic mutation. If a person has a family history of sickle cell anemia, it is recommended to see a genetic counselor before planning a pregnancy. The doctor will examine the couple and assess the likelihood of having a child with sickle cell anemia.
Sickle Cell Anemia Clinical Trials
Visionaries Clinical Research is currently recruiting volunteers to participate in Phase 1 clinical trial to evaluate the efficacy and safety of an investigational drug in patients with sickle cell anemia. This study will include patients aged between 18 and 65 years (inclusive).
Interested in participating in a clinical trial?