Sickle cell disease (SCD) is a group of lifelong genetic conditions that affect the form and function of your red blood cells. People with SCD make abnormally shaped red blood cells. These red blood cells can’t live as long as healthy red blood cells and can block your blood vessels.
This causes serious health problems such as:
- anemia
- pain
- lung problems
- delayed growth
- increased risk of developing infections
- stroke
To inherit SCD, you must have two parents who carry sickle cell trait (SCT). But most people with parents who carry the trait don’t inherit SCD. Instead, they may carry the trait, which they can pass on to their children.
Having SCT isn’t the same as having SCD. But in rare cases, some people who carry the trait can experience some of the same severe symptoms of SCD.
A person with SCT inherits one sickle cell gene and one regular gene from their parents.
If both your parents carry the trait, it means they each have one regular and one sickle cell gene. You then have a:
- 25% chance of getting both sickle genes and having SCD
- 50% chance of getting one sickle gene and one regular gene and having SCT
- 25% chance of getting two regular genes and being unaffected
If you have relatives with SCT or SCD, you’re at higher risk of both.
A medical professional can diagnose SCT or SCD with a simple blood test.

Medical Illustration by Bailey Mariner
Most people with SCT don’t have any symptoms of SCD. But under certain conditions, some people with SCT may experience serious symptoms linked to SCD. Under these stressful conditions, healthy red blood cells in people with SCT can become sickle shaped.
Conditions that might cause symptoms in people with SCT include:
- severe hypoxia, or low oxygen levels in your body tissue
- dehydration
- increased stress
- hypothermia or hyperthermia
- inflammation
Some of the severe symptoms and complications
- asymptomatic bacteriuria in pregnant people
- hematuria (blood in urine)
increased chronic kidney disease - fetal loss and other pregnancy complications
- muscle breakdown
- severe pain
- renal papillary necrosis (a serious kidney disorder)
- splenic infarction
- sudden death due to exertion
Sickle cell trait in athletes
After a 19-year-old college athlete suddenly died during intense football training, the National Collegiate Athletic Association (NCAA) implemented a
Athletes and others with SCT who exert themselves physically, such as people in the military, may have a greater risk of more severe symptoms. If you’re in this group and have SCT, you’re more likely to experience heat stroke and muscle breakdown during bouts of intense exercise. Your risk is highest under extreme temperatures and severe conditions.
According to researchers, people with SCT have a
People participating in athletics who have SCT need to be mindful during training and competition. To prevent serious complications linked to SCT:
- Drink lots of water before, during, and after training and competition.
- Get immediate medical treatment when you feel ill.
- Keep a cool body temperature when exercising in hot and humid conditions. Mist your body with water or move to an air-conditioned space during breaks or rest periods.
- Set your own pace for physical activities and build intensity slowly.
- Rest in the shade between drills and sets.
SCT is a lifelong genetic trait. People with SCT prone to medical complications should avoid situations that will put their bodies under additional stress. Situations to avoid include:
- dehydration or drinking too little water
- exposure to increased atmospheric pressure, such as when scuba diving
- high altitudes, such as air travel, visiting a high-altitude place, or mountain climbing
- low oxygen levels in the air, such as when mountain climbing, training for athletic competition, or completing military boot camp
- extreme exercise
- sudden temperature changes
When mild symptoms of SCT arise, it’s possible for many people to manage them at home. Some people find the following actions can help ease symptoms:
- Apply a warm towel or wrapped heating pad to the affected part of your body.
- Distract yourself with a movie or book.
- Drink plenty of water.
- Take over-the-counter pain relievers, such as ibuprofen.
If you have a case with severe symptoms, see a medical professional right away.
If you have SCT, you might have questions about how it can affect your life. Here are answers to some common questions.
Does sickle cell trait increase my risk of serious COVID-19 infection?
According to researchers, people with SCD and SCT have risk factors that make them more likely to experience serious coronavirus disease 19 (COVID-19) infection and death compared with the general population. Early evidence suggests that people with SCT may be more likely to be hospitalized or die from COVID-19, particularly African American people assigned male at birth. More long-term research on SCT and COVID-19 is needed to understand the full range of effects.
Do people with sickle cell trait have a lower life expectancy?
According to experts, people with SCT tend to have a
How can I find out if I have sickle cell trait?
Doctors or healthcare professionals can diagnose SCT with a simple blood test. You may want a doctor to test you for SCT if you have one or more family members who carry the trait or have SCD. If you learn that you or a loved one has SCT, schedule an appointment to talk with a healthcare professional.
You may also want to schedule a visit with a genetic counselor to learn more about what the diagnosis means and how it can affect you and your family.
How common is sickle cell trait?About
300 million people globally have SCT. It’s most common among people of African or Caribbean ancestry. About 1 in 12 African Americans has the trait.
SCT is a genetic trait that can, in rare cases, cause serious symptoms linked to SCD. While SCT usually doesn’t cause complications, some of the more severe risks include pregnancy complications, muscle breakdown, and even sudden death. In more mild cases, you can manage symptoms at home.
The best way to prevent complications of SCT is to avoid situations that may trigger severe symptoms, such as strenuous exercise, scuba diving, or mountain climbing. Athletes with SCT must be cautious about exerting themselves and ensure they stay cool, rested, and hydrated.
It’s possible to live a fulfilling, healthy life with SCT. Knowing how to avoid serious complications can help you live life to the fullest with little to no symptoms.