What Is Thalassemia?

What Is Thalassemia?
By: Peter Hutch

Thalassemia is the name of a group of genetic blood disorders. To understand how thalassemia affects the human body, you must first understand a little about how blood is made. Hemoglobin is the oxygen-carrying component of the red blood cells. It consists of two different proteins, an alpha and a beta. If the body doesn't produce enough of either of these two proteins, the red blood cells do not form properly and cannot carry sufficient oxygen. The result is anemia that begins in early childhood and lasts throughout life.

Thalassemias are caused by a mutation in the beta globin chain. The mutated genes must be inherited from both parents to acquire the major form of this disease. If one mutated gene is inherited, the person will be a carrier of the disease, but will not have symptoms. This is the minor form of the disease.

In the major form, children are normal at birth, but develop anemia during the first year of life. Growth failure, bone deformities, and enlarged liver and spleen are some of the problems that can occur. Blood transfusions may modify some of the signs of the disease, but iron overload from the transfusions may cause damage to the heart, liver, and endocrine systems.

In the most common type of β thalassemia trait, the level of Hb A2 (δ2/α2) is usually elevated. This is due to the increased use of δ chains by the excessive free α chains, which results from a lack of adequate β chains with which to pair. The δ gene, unlike β and α genes, is known to have a physiologic limitation in its ability to produce adequate δ chains; by pairing with the α chains, δ chains produce Hb A2 (approximately 2.5-3% of the total Hb).

Thalassemia, a genetic disease, can be mild or severe. Some carriers of the gene have no symptoms. The most common severe form in the United States is a type called Cooley's anemia. It mainly affects people of Mediterranean or Asian ancestry. It usually appears during the first two years of life. Severe thalassemia is treated with blood transfusions and treatment to remove excess iron in the blood.

In beta thalassemia major there is a complete failure of beta
chain production. Hence there is very little, if any, Hgb A present. Delta and gamma chain production is increased. As a result there is raised levels of Hgb A2 and Hgb F. Hemoglobin F has a very high

affinity for oxygen and is a poor oxygen deliverer. As a result the only functional hemoglobin present is Hgb A2, hence the patient is hypoxic which causes increased erythropoietin secretion.

Thousands of patients receive medical care outside of specialized thalassemia centers. These patients and providers need information concerning recommendations for comprehensive screening tests, access to new research protocols and treatment including transfusion therapy, new chelation therapy, stem-cell transplantation, hormone replacement, heart disease, osteoporosis and hepatitis.

Quality of life for families and patients can be excellent with a future including employment, marriage and children. To achieve this, families and providers need information concerning psychological wellness, cultural issues and counseling for family planning and marriage.

Thalassemia is a quantitative problem of too few globins synthesized, whereas sickle-cell disease (a haemoglobinopathy) is a qualitative problem of synthesis of a non-functioning globin. Thalassemias usually result in under production of normal globin proteins, often through mutations in regulatory genes.

Hemoglobinopathies imply structural abnormalities in the globin proteins themselves. The two conditions may overlap, however, since some conditions which cause abnormalities in globin proteins (hemoglobinopathy) also affect their production (thalassemia).

By: Peter Hutch

Article Directory: http://www.articledashboard.com