Thalassemia is a blood disorder. It cuts down the amount of red blood cells and hemoglobin that the body can make. Red blood cells carry oxygen to all the organs in the body. Hemoglobin is a part of red blood cells that help grab oxygen at the lungs. Low levels of red blood cells and hemoglobin can lead to anemia. Anemia interferes with normal bodily functions.

Hemoglobin
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Thalassemias are split into two main categories. The categories are based on the part of hemoglobin that is affected:

  • Alpha thalassemia—based on the alpha part of hemoglobin
  • Beta thalassemia—based on the beta part of hemoglobin

Thalassemia is caused by faults in specific genes. It is an inherited disorder. This means the affected person received the faulty genes from the parents. The severity of the thalassemia will depend on the number of faulty genes that a child inherits. There are four genes needed for hemoglobin, two from each parent. The number of genes that are faulty will determine the severity and subtype of thalassemia:

  • In alpha thalassemia:
    • One abnormal gene—silent carrier, no signs of illness but can pass condition on to child
    • Two abnormal genes—thalassemia trait, may have mild anemia
    • Three abnormal genes—Hemoglobin H disease, moderate to severe anemia
    • Four abnormal genes—most severe form called Alpha hydrops fetalis, results in fetal or newborn death
  • In beta thalassemia:
    • One abnormal gene—Thalassemia minor, carrier with mild anemia
    • Two abnormal genes—Thalassemia major known as Cooleys anemia, may have moderate to severe anemia