Sickle cell trait is a genetic feature that affects the blood. Usually, a person who has it has no symptoms, but they may need to take a few extra precautions. It is different from sickle cell disease.
In medical terms, a trait is an inherited feature. A person with sickle cell trait (SCT) has inherited one atypical hemoglobin gene from one biological parent and another gene without this characteristic from the other. Hemoglobin is a protein in red blood cells that carries oxygen around the body.
SCT is an inherited disorder that affects red blood cells. It occurs in 1–3 million individuals in the United States.
In this article, learn what SCT is and what it means for the people who have it.
People with SCT have inherited one gene for typical hemoglobin and one for sickle cell hemoglobin. Inheriting only one of the genes that causes it is what makes sickle cell trait different from sickle cell disease.
In the U.S., SCT is most common among African Americans, affecting 8–10% of these individuals. It also occurs in other ethnicities, including Hispanic Americans from Central and South America and people of southern Europe, Middle Eastern, Asian, Indian, and Mediterranean descent.
Sickle cell disease occurs when a person inherits two sickle cell genes — one from each biological parent. This makes red blood cells hard, sticky, and shaped similar to sickles.
Sickle-shaped cells die quickly, so people with the disease have a shortage of red blood cells. These sickle-shaped cells can also clog smaller blood vessels and cause serious health issues.
Most people with SCT have no medical issues as a result — the trait cannot develop into the disease.
While symptoms are rare, they can include blood in the urine or general pain and discomfort. Circumstances that can trigger the symptoms
- being at high altitudes, such as when flying or mountain climbing
- performing intense exercise, especially if it leads to dehydration
- being in environments at high pressure, such as when scuba diving
Under a microscope, the blood cells of a person with SCT usually
Most individuals with SCT experience
- muscle breakdown, called rhabdomyolysis, during exercise or training, especially in high or low temperatures
- low blood supply to the spleen, leading to tissue death
- glaucoma, following an eye injury
- kidney disease
- renal medullary carcinoma, a rare form of kidney cancer
There is also a higher risk of sudden death due to exertion.
While most experts consider SCT to be benign, there is some
Meanwhile, more funding is necessary for research and awareness of sickle cell disease worldwide. In the U.S., this area of health receives
The lack of funding for SCT and sickle cell disease stems from inequity in healthcare, a problem that health experts state needs urgent addressing.
It is possible to
For this reason, it is crucial to understand how the trait passes on and how likely people can inherit the feature.
- a 50% chance their child will have the trait
- a 25% chance their child will have sickle cell disease
- a 25% chance their child will have neither the trait nor the disease
However, if only
Anyone with concerns about the chances of passing on the trait should discuss the implications and testing options with a doctor.
Since sickle cell disease symptoms can start as early as
For older children and adults, a doctor can
Insurance often covers testing for SCT. Screening is also routine for athletes and people joining the military.
SCT usually requires
However, a person may wish to consult a doctor if they know they have the trait and are planning to:
- have children
- be an athlete
- join the military
Considerations during extreme exercise
People with SCT are
Therefore, it is crucial to avoid getting overheated and dehydrated during physical activity. Tips include:
- building up the intensity of workouts slowly
- resting between sets and drills
- drinking plenty of water before, during, and after activity
- keeping cool by misting with water or going to an air-conditioned area during breaks
- receiving medical care immediately if any symptoms of illness develop
Considerations during pregnancy
If a person knows that they have SCT, they can speak with a genetic counselor before having children.
The counselor will look at the family histories of the individual and their partner and discuss any relevant risks and considerations.
SCT is a genetic feature. Most people who have it experience no symptoms, but there is a higher risk of certain complications, so taking precautions may be necessary, such as during extreme exercise.
A person can pass the trait on, and if both biological parents have the trait, their child may have sickle cell disease, a different issue that can be serious.
For this reason, health experts recommend that anyone with SCT speak with a genetic counselor before having children.