First Time User? Enroll now.
As the COVID-19 situation has evolved, our visitor policy is evolving as well. Get full details.
For the most current information, please visit our Coronavirus resource pages.
Home > Health Library > Sickle cell trait
Sickle cell trait occurs when a person inherits a sickle cell disease gene but does not develop symptoms. Sickle cell disease is a blood disorder in which the body produces an abnormal type of the oxygen-carrying substance hemoglobin in the red blood cells.
Normal hemoglobin is called hemoglobin A, but people with sickle cell disease have only hemoglobin S, which turns normal, round red blood cells into abnormally curved (sickle) shapes.
Normally, a person inherits two genes (one from each parent) that produce beta-globin, a protein needed to produce normal hemoglobin (hemoglobin A). A person with sickle cell trait inherits one normal beta-globin gene (hemoglobin A) and one defective gene (hemoglobin S).
People with sickle cell trait rarely have symptoms due to the condition, because they also have some normal hemoglobin. But they can pass the sickle cell gene to their children.
A person in whom both beta-globin genes are abnormal (they produce hemoglobin S) has sickle cell disease, which can cause serious problems. Both parents must have either the sickle cell trait or the disease itself for a child to have sickle cell disease.
Current as of: March 3, 2021
Author: Healthwise Staff
Medical Review:E. Gregory Thompson MD - Internal Medicine & Adam Husney MD - Family Medicine & Martin J. Gabica MD - Family Medicine & Martin Steinberg MD - Hematology
To learn more about Healthwise, visit Healthwise.org.
© 1995-2021 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
Feeling under the weather?
Use our interactive symptom checker to evaluate your symptoms and determine appropriate action or treatment.
Get started learning more about your health!
Our Interactive Tools can help you make smart decisions for a healthier life. You'll find personal calculators and tools for health and fitness, lifestyle checkups, and pregnancy.