People with the thalassemia trait, or thalassemia carriers, may not experience any symptoms. However, some thalassemia carriers can experience anemia symptoms, such as paleness and fatigue.

In people with thalassemia, the body does not produce enough of the protein hemoglobin, which allows red blood cells to transport oxygen to tissues around the body.

It is an inherited condition, meaning that a child has one or several missing or altered genes that support their ability to produce hemoglobin. Problems with hemoglobin production occur in people with thalassemia because these genes affect how the body makes two proteins: Alpha globin and beta globin. These proteins are the two major components of hemoglobin.

People who inherit altered genes or are missing genes from just one parent but not the other may have the “thalassemia trait” but not develop thalassemia themselves.

This article explores possible signs of thalassemia trait, why thalassemia develops, and how doctors diagnose and treat it.

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According to the United Kingdom’s National Health Service (NHS), people who carry the altered genes that can cause thalassemia without developing the condition are known as carriers. Some doctors describe this as thalassemia minor or having the thalassemia trait.

Thalassemia carriers never develop the condition, but they may experience anemia symptoms, which can include:

Sometimes, a person with thalassemia trait may never experience symptoms.

People with the thalassemia trait can pass on the genes that cause thalassemia to their children. If a partner also has the thalassemia trait, the risk of any resulting child developing thalassemia is as follows:

  • The child will not have thalassemia or carry the trait: 25%
  • The child will be a carrier but not develop thalassemia: 50%
  • The child will develop thalassemia: 25%

People with the thalassemia trait may develop mild anemia symptoms due to red blood cells that are smaller than usual, even if they do not have thalassemia, according to the NHS.

The different types of thalassemia develop due to genetic mutations or deletions (where genetic code is missing) in the genes that support alpha and beta globin production. Abnormalities in these genes mean the body cannot get enough oxygen to its tissues and organs, as oxygen usually binds to hemoglobin in red blood cells to reach them.

Four genes are responsible for making alpha globin. The more genes a person is missing, the more severe their alpha thalassemia will be. People missing one gene will be carriers. Infants missing all four genes often die during birth or shortly after.

Two genes play a role in beta globin production. If one of these has changes, a person will have the thalassemia trait and may experience mild beta-thalassemia. If both have changes, a person will have either moderate or severe beta-thalassemia.

Risk factors

Two main risk factors can make thalassemia more likely.

The first is family history. Thalassemia passes on in an autosomal recessive inheritance pattern. This means that both parents must be carriers or have thalassemia for the condition to develop. If a person only inherits the thalassemia trait from a single parent, they may become a carrier but will not develop thalassemia.

Secondly, thalassemia is most common in people with the following heritage:

  • South Asian
  • Italian
  • Greek
  • Middle-Eastern
  • African

People of South Asian descent may be at a higher risk of severe alpha-thalassemia, resulting from missing two of the genes with links to alpha globin production.

Blood testing can help diagnose thalassemia. If a person is not showing symptoms or the symptoms are minor, a doctor may suspect thalassemia on the basis of the results of routine blood tests.

People with more severe thalassemia tend to experience serious symptoms before they reach 2 years of age.

A doctor may ask a person about family history or whether another individual in the family has thalassemia. They may also check a person’s medical history for signs of thalassemia.

The following tests can help diagnose thalassemia:

  • a complete blood count (CBC), which shows the amount of hemoglobin and different types of blood cells in the blood
  • special hemoglobin tests, which measure the types of hemoglobin and can help healthcare professionals identify different conditions that affect hemoglobin
  • genetic testing, which can help doctors define the type of thalassemia a person has

People with mild anemia symptoms due to the thalassemia trait or those who carry the trait without showing symptoms do not require treatment. Thalassemia will not develop, and carrying the gene will not directly cause any extra health problems.

The anemia symptoms that may develop do not have the same cause as iron deficiency anemia, so thalassemia carriers should avoid taking iron supplements unless they receive an iron deficiency diagnosis. The supplements can lead to excess iron in the body and may cause harm.

For people who develop moderate to severe thalassemia, treatments include:

  • Blood transfusions: A doctor uses a needle to insert an intravenous (IV) drip into an arm before transferring healthy blood with typical hemoglobin levels into the body. These may either be occasional or regular, depending on the type of thalassemia.
  • Iron chelation therapy: Iron may build up after regular blood transfusion, leading to iron overload, which can be life threatening. People may need to undergo iron chelation therapy, which removes excess iron using drugs such as deferiprone, deferasirox, or deferoxamine.
  • Bone marrow transplant: Only a bone marrow transplant, or hematopoietic stem cell transplant, can fully cure thalassemia. However, people with thalassemia may not be suitable for surgery, and finding a good match to donate bone marrow may not be possible.
  • Medications: These include hydroxyurea and luspatercept (Reblozyl). Hydroxyurea is a sickle cell anemia treatment that can reduce thalassemia-related health problems. People can take luspatercept to reduce the number of blood transfusions they need.
  • Splenectomy: A physician may recommend removing the spleen to improve mild-to-moderate thalassemia symptoms. However, this can impact the immune system’s ability to manage infections.

Thalassemia carriers typically do not experience thalassemia symptoms, but they may experience anemia symptoms, such as fatigue and skin paleness. Because they have only inherited a single mutated or deleted gene that affects hemoglobin production, they will never experience significant health problems due to thalassemia.

To develop thalassemia, a person needs to acquire the mutated or deleted genes from both parents. Thalassemia carriers do not typically need to receive treatment and should not take iron to treat anemia symptoms unless they receive an iron anemia deficiency diagnosis.

People should speak with a healthcare professional if they experience symptoms that may indicate anemia. A doctor can recommend appropriate treatment if necessary.