People with sickle cell trait inherit a sickle cell gene from 1 parent and a normal gene from the other parent. They usually do not have sickle red blood cells or any symptoms of sickle cell disease (SCD). However, intense exercise can cause serious complications in athletes with sickle cell trait.
If you have sickle cell trait and want to have a child, talk to your doctor. They can refer you to a genetic counselor, who specializes in the genetics of inherited conditions. They can explain the risks and help prepare you for different outcomes.
How do I know if my child or I have sickle cell trait?
Sickle cell trait is diagnosed with a simple blood test. All babies in the United States are tested when they are born. The test uses blood from a newborn’s heel or finger to identify abnormal types of hemoglobin.1,2
Newborns with sickle cell trait have 3 types of hemoglobin:3
- Fetal hemoglobin (HbF)
- Normal hemoglobin (HbA)
- Sickle hemoglobin (HbS)
This is called an FAS pattern. Within a few months, HbF levels will decrease and the child will only have HbA and HbS. This is then called HbAS.3
Many older children and adults with sickle cell trait may be unaware of their diagnosis. It is common for people to forget or never know their diagnosis because they never showed symptoms. Diagnostic testing is often then done later in life when a family member is diagnosed with sickle cell trait or SCD. Testing is available at most hospitals and medical centers.4
What is the risk of my child having sickle cell disease if I have sickle cell trait?
When you have a child, you will pass down 1 of your 2 copies of the hemoglobin gene. This means there is a 50 percent chance you will pass down the sickle hemoglobin gene.
If your partner also has a copy of the sickle hemoglobin gene, there is a chance your child will have sickle cell disease. For example, if you and your partner both have sickle cell trait:5
- There is a 50 percent chance your child will have sickle cell trait
- There is a 25 percent chance your child will have SCD
- There is a 25 percent chance your child will not have sickle cell trait or SCD
If you have sickle cell trait and your partner has SCD, your child will inherit at least 1 sickle hemoglobin gene. There is a 50 percent chance your child will have SCD and a 50 percent chance your child will have sickle cell trait.
If you want to have a child, talk to your doctor or a genetic counselor. They can discuss the risks and help you prepare for potential outcomes.
What health problems can people have?
Most people with sickle cell trait do not have sickle red blood cells and do not experience any symptoms of sickle cell disease. However, there have been rare instances of people with sickle cell trait experiencing pain crises and other complications. In these rare cases, complications are usually triggered by:5
- Increased atmospheric pressure (like scuba diving)
- Low oxygen levels (like mountain climbing or doing intense exercise)
- Dehydration
- High altitudes
Intense exercise can cause red blood cells to become sickled in people with sickle cell trait. This is often called “exertional sickling.” Some people with sickle cell trait have experienced heat stroke and muscle breakdown (rhabdomyolysis) during intense exercise. About 5 percent of sudden sports deaths in student athletes over the past decade have been caused by exertional sickling.6-9
The risk of complications during exercise is lower if you stay hydrated and avoid extreme temperatures. When participating in intense training or sports, it is important to:5,6
- Set your own pace and rest often
- Drink plenty of water before, during, and after exercise
- Keep your body temperature cool in hot temperatures
- Stop activities if you feel cramping, pain, swelling, weakness, breathlessness
- Get medical care immediately when feeling ill