Dear Doctor Column, October 20, 2003

Thalassemia is an Inherited Disease

Question:

My aunt told me that our family has a heredity disease called thalassemia. I am trying to find some information on the subject. Can you help?

Answer:

We can give you some general information on the disease and provide you with links to thalassemia-related Web sites.

The thalassemias are a group of genetic (inherited) blood disorders that affect a person's ability to produce hemoglobin — the protein in red blood cells that carries oxygen and nutrients throughout the body. Both parents must have the thalassemia trait in order to pass the disease to their children, but it only takes one parent to pass the trait on to a child.

The thalassemias are divided into two main types: alpha thalassemia and beta thalassemia. Within each type, there are three classifications: thalassemia minor (or trait), thalassemia intermedia, and thalassemia major (disease). Sometimes, Cooley's anemia is used to describe beta thalassemia major.

A person with thalassemia minor will experience no significant health problems, except possibly a mild anemia that is not treatable with iron supplements. Thalassemia intermedia is an intermediate form of disease requiring regular health care. Thalassemia major is a serious disease requiring regular blood transfusions and extensive medical care.

If left untreated, a child with thalassemia major can experience several or all of the following signs and symptoms: severe anemia, jaundice, an enlarged spleen, fatigue, listlessness, reduced appetite, enlarged and fragile bones, facial malformation, growth problems, and increased susceptibility to infection. Without treatment, oxygen and nutrients cannot get to the body's tissues and organs, leaving them unable to function properly. In parts of the world where blood is not readily available, many children die of severe thalassemic anemia. However, those who receive regular transfusions and undergo iron removal therapy can avoid many of these symptoms.

Descendants from Southeast Asia, southern China, the Middle East, the Mediterranean (Greece, Italy, Turkey), parts of North Africa, and parts of the Pacific Islands are at an increased risk for thalassemia. In fact, thalassemia is the most common inherited single gene disorder in the world; boys and girls are equally affected.

Because individuals with thalassemia major cannot produce enough hemoglobin to survive, they need a blood transfusion every 3 to 4 weeks in order to grow and live normally. However, there are risks associated with chronic blood transfusion, including exposure to blood-borne infections, transfusion reactions such as fever or rash, and alloimmunization, which occur when a person who has repeated blood transfusions develops antibodies against the donated blood.

The greatest problem associated with chronic transfusion is iron overload. Since the body has no way of ridding itself of excess iron, iron begins to deposit in the body's organs, especially the heart, liver, and pituitary gland. It also affects normal development and bone growth. Chronically transfused patients must take a nightly infusion of deferoxamine (Desferal) to remove the excess iron.

Currently, the only cure for thalassemia is a bone marrow transplant (BMT), which also carries significant risk. A recent development in transplantation involves using blood from the umbilical cord from a newborn baby. Transplants that use umbilical cord blood generally have fewer complications than cells collected from a similar adult donor. Gene therapy also is being explored.

A blood test can determine if you have thalassemia trait. If you want to test your baby for disease, talk with your obstetrician. You also might want to consult a genetic counselor.

For more information, visit Cooley's Anemia Foundation; the U.S. Department of Health and Human Services (and its alternative Web site); and the March of Dimes.