Sickle Cell Trait

People who inherit one sickle cell gene and one normal gene have sickle cell trait (SCT). Sickle cell trait (SCT) is an inherited blood disorder. People with SCT usually do not have any of the symptoms of sickle cell disease (SCD), but they can pass the trait on to their children.

SICKLE CELL TRAIT AND INHERITANCE

Sickle cell trait is passed on from parent to child. If both parents have SCT, their biological children have a 50% chance of having SCT and a 25% chance of having the more serious sickle cell disease. If just one parent has sickle cell trait, their children have a 50% chance of inheriting SCT, but do not have any chance of developing SCD.

HOW SICKLE CELL TRAIT IS INHERITED

  • If both parents have SCT, there is a 50% (or 1 in 2) chance that any child of theirs also will have SCT, if the child inherits the sickle cell gene from one of the parents. Such children will not have symptoms of SCD, but they can pass SCT on to their children.
  • If both parents have SCT, there is a 25% (or 1 in 4) chance that any child of theirs will have SCD. There is the same 25% (or 1 in 4) chance that the child will not have SCD or SCT.

DIAGNOSIS

SCT is diagnosed with a simple blood test. People at risk of having SCT can talk with a doctor or health clinic about getting this test.

COMPLICATIONS

Most people with SCT do not have any symptoms of SCD, although—in rare cases—people with SCT might experience complications of SCD, such as pain crises.
In their extreme form, and in rare cases, the following conditions could be harmful for people with SCT:

  • Increased pressure in the atmosphere (which can be experienced, for example, while scuba diving).
  • Low oxygen levels in the air (which can be experienced, for example, when mountain climbing, exercising extremely hard in military boot camp, or training for an athletic competition).
  • Dehydration (for example, when one has too little water in the body).
  • High altitudes (which can be experienced, for example, when flying, mountain climbing, or visiting a city at a high altitude).

More research is needed to find out why some people with SCT have complications and others do not.