Thalassemia Minor and Genetics

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Thalassemia Minor and Genetics

Question:

Both my husband and I are from the Mediterranean area and have been diagnosed with Mediterranean anemia (thalassemia minor). How will this affect our children? What do I need to know before getting pregnant?

Answer:

Thalassemias are a type of blood disorder. Red blood cells contain hemoglobin, a protein that latches onto oxygen from the lungs and delivers the oxygen to all the body's tissues.

Thalassemia interferes with the body's ability to make hemoglobin. In beta thalassemia, the beta-globin gene carries a genetic change. Everyone has two beta-globin genes, one from each parent. People with a genetic change in both beta-globin genes have thalassemia major. This causes significant medical problems and a shortened life expectancy. People with one genetic change have thalassemia minor, a mild form of anemia. Most people with thalassemia minor don't have symptoms related to the mild anemia.

Two people with thalassemia minor have a 25% chance of having a child with thalassemia major each time they become pregnant. The first step is to confirm the genetic change in you and your husband through prenatal testing. Early in the pregnancy, a doctor can use either chorionic villus sampling or amniocentesis to get a sample of tissue from the fetus. A lab then tests the tissue sample to determine if the fetus has inherited the disease. If you are using in vitro fertilization, you may be able to have the embryo examined right after the egg and sperm are combined and before it is implanted in the womb. Your obstetrician or a genetic counselor can help you with these options.

Other blood conditions that can give the appearance of thalassemia minor so it's important to get an accurate diagnosis. If you get a genetic test, you can be sure of your risk. A genetic counselor or hematologist can help you to understand these complex issues.

David T. Miller, M.D., Ph.D. is a clinical geneticist at Children's Hospital, Boston and an Instructor at Harvard Medical School. He is also Assistant Director of the DNA Diagnostic Laboratory at Children's Hospital.

Last updated:	July 20, 2009