Alpha Thalassemia

What is alpha thalassemia?

Thalassemia is a blood disorder
that is inherited. This means it is passed down from one or both parents through their
genes. When you have thalassemia, your body makes less hemoglobin than normal.
Hemoglobin is an iron-rich protein in red blood cells. It carries oxygen to all parts of
the body.

There are 2 main types of
thalassemia: alpha and beta. Different genes are affected for each type.

Thalassemia can cause mild or
severe anemia. Anemia occurs when your body does not have enough red blood cells or
hemoglobin. The severity and type of anemia depends on how many genes are affected.

How to say it

thal-uh-SEE-mee-uh

What causes alpha thalassemia?

Alpha thalassemia occurs when one
or more of the 4 alpha-globin genes that make up part of the hemoglobin molecule are
missing or damaged.

There are 4 types of alpha thalassemia:

  • Alpha thalassemia silent carrier. One gene is missing or
    damaged, and the other 3 are normal. Blood tests are often normal. Your red blood
    cells may be smaller than normal. Being a silent carrier means you don’t have signs
    of the disease, but you can pass the damaged gene on to your child. This is confirmed
    by DNA tests.
  • Alpha thalassemia carrier. Two genes are missing. You may
    have mild anemia.
  • Hemoglobin H disease. Three genes are missing. This leaves
    just 1 working gene. You may have moderate to severe anemia. Symptoms can worsen with
    fever. They can also get worse if you are exposed to certain medicines, chemicals, or
    infectious agents. Blood transfusions are often needed. You have a greater risk of
    having a child with alpha thalassemia major.
  • Alpha thalassemia major. All 4 genes are missing. This
    causes severe anemia. In most cases, a baby with this condition will die before
    birth.

Who is at risk for alpha thalassemia?

This is a genetic disease inherited from one or both parents. The only risk factor is having a family history of the disease.

What are the symptoms of alpha thalassemia?

Different people will have different symptoms, based on which type of alpha thalassemia is inherited. Common symptoms for each type may include:

  • Silent alpha thalassemia carrier. This type has no
    symptoms.
  • Alpha thalassemia carrier. You may have mild anemia. You
    may have no symptoms. Or you may have mild symptoms such as mild fatigue or trouble
    doing normal amounts of physical activity (exercise intolerance).
  • Hemoglobin H disease. This type causes moderate to severe
    symptoms. These include fatigue and exercise intolerance. You may also have an
    enlarged liver or spleen, yellowish skin, and leg ulcers. You have a greater risk of
    having a child with the most severe type, alpha thalassemia major.
  • Alpha thalassemia major. Babies with this type often die
    before they are born.

How is alpha thalassemia diagnosed?

Alpha thalassemia is most often
found in these parts of the world:

  • Africa
  • Middle East
  • India
  • Southeast Asia
  • Southern China
  • Mediterranean region

The following blood tests are done
to check for the condition and to tell if you are a carrier, and can pass the disorder
on to your children:

  • Complete blood count (CBC). This test checks the size,
    number, and maturity of different blood cells in a set volume of blood.
  • Hemoglobin electrophoresis. A lab test that tells what
    type of hemoglobin is present.
  • Ferritin. This test is done to rule out iron-deficiency
    anemia.
  • DNA testing.
    This test identifies which alpha globin genes are present, absent, or
    damaged.

All of these tests can be done using a single blood sample. In a pregnant woman, the baby is diagnosed using CVS (chorionic villus sampling) or amniocentesis. A DNA test is needed to make a diagnosis of alpha thalassemia.