American Medical Association Family Medical Guide - American Medical Association [368]
When thalassemia results from a defect in the production of the alpha protein, it is called alpha thalassemia. Because each parent provides two alpha protein genes, people with this form of thalassemia are usually not severely affected because the healthy two or three copies of the protein override the impact of the deficient ones.
The most serious form of the disorder, called beta thalassemia major, is caused by a deficiency or complete absence of the beta hemoglobin protein. Beta thalassemia major, which occurs when a child inherits a copy of the defective gene from both parents, causes severe anemia. When a person inherits the beta protein defect from only one parent, he or she has what is called thalassemia trait, which rarely causes any serious symptoms or health problems. Thalassemia trait is much more common than beta thalassemia major. The two forms of beta thalassemia can have varying degrees of severity that still allow a person to lead a relatively normal, healthy life.
Symptoms
The form of alpha thalassemia that is most common in the United States, especially among African Americans and Asians, makes the red blood cells smaller than normal but usually does not produce symptoms. The symptoms that can occur in the various forms include poor growth in an infant, enlargement of the spleen, severe anemia, and jaundice (yellowing of the skin and whites of the eyes). Children with thalassemia may have delayed sexual development and skull deformities. If your child has any of these signs or symptoms, see your doctor right away.
Diagnosis
To diagnose thalassemia, a doctor will order a blood test to detect the abnormal gene. If you have any form of the disease in your family, including thalassemia trait, and are considering having a child, talk to a genetic counselor (see page 952) about your risks of passing the gene on to a child. Thalassemia can be diagnosed in a fetus early in pregnancy with chorionic villus sampling (CVS; see page 511) or later in pregnancy with amniocentesis (see page 510).
Treatment
A child with thalassemia major needs to have regular blood transfusions to provide healthy red blood cells to relieve the symptoms of anemia. These transfusions may use only young red blood cells, which survive longer than older cells, thereby reducing the number of transfusions necessary. However, frequent transfusions eventually lead to a buildup of iron in the body, which can damage the liver and heart. For this reason, a person with thalassemia needs to have the iron removed regularly. To remove some of the excess iron, a drug called deferoxamine is infused under the skin overnight for a number of nights, depending on the iron level in the blood. In extremely severe cases, a stem cell transplant (see page 624) may be considered, although it carries significant risks.
Hemolytic Anemia
Hemolysis is a process in which red blood cells are destroyed prematurely. When hemolysis occurs, the body attempts to compensate by producing new red blood cells. If the destruction of cells exceeds cell production, the resulting disorder is hemolytic anemia. Hemolytic anemia may be inherited and present at birth, or it may be acquired later in life. Inherited hemolytic anemia may occur because the red blood cells do not have enough of a specific enzyme to protect themselves in the presence of some medications or the stress of an infection. Sickle cell disease (see page 613) is an example of inherited hemolytic anemia.
One type of acquired hemolytic anemia occurs when the body mistakenly produces antibodies (proteins that fight specific germs recognized by the body) that destroy the body’s own red blood cells. Normally, an immune system organ called the spleen eliminates defective, damaged, or old red blood cells from the