A closer look at thalassemia major and minor

Courtesy by: Silive.com

STATEN ISLAND, N.Y. — Thalassemias are disorders of the blood, more specifically of the red cells. The red cells are those particles necessary to carry oxygen to the different parts of the body. Their role is paramount. The red cells, despite their relative simplicity compared to other cells (for instance, they do not have a nucleus), are still extremely complex in order to achieve their important function.

The word “thalassemia” comes from thalassa, meaning “sea” in Greek. It’s a disease that is quite prevalent in areas around the Mediterranean Sea (Greece and Italy). It is estimated that about 15 percent of Staten Islanders carry the gene of thalassemia, given the presence of Italian ancestry in the borough’s demographics.

The thalassemias are hereditary disorders that cause anemia. Anemia is a condition in which the number of the red cells or the content in hemoglobin of the red cells is reduced. Many disorders may cause anemia, and there are different types of anemia. Iron, vitamin B-12, folate deficiencies, chronic disorders, tumors, kidney insufficiency, bone marrow abnormalities (just to mention a few) may cause anemia. Normally, the red cell number is between 4 to 5 million per millimeter cube and the hemoglobin is between 12 to 16 g/dl for women and 14 to18 for men. Anemia occurs when those numbers decrease.

The red cells are made by a membrane and internal components, including enzymes, electrolytes and hemoglobin, among others.

In thalassemias, it’s the hemoglobin that’s abnormal. It is the molecule needed to bind the iron. It is essentially the complex structure to carry oxygen to the tissues. The hemoglobin is composed by the “globin,” which is made by four chemical chains (alpha and beta) and the “heme” which is the core for the iron. In thalassemias the globin is deficient. There is a lack of the appropriate quantity of the chains. The most common variety found in Staten Island is the beta-thalassemia defined by a total (thalassemia major or Cooley’s anemia) or partial lack (thalassemia minor) of beta chains. In the African-American community, the alpha-thalassemia is more common. Both sexes are equally affected.

CLINICAL ASPECT

Without going into too many details, let’s review the clinical aspect of this disorder from a layman’s perspective. The Cooley’s anemia (thalassemia major) is the one that is more dreaded. It is the homozygous form of the disease (in other words, the patient has inherited the thalassemia gene from both parents).

The clinical picture is quite devastating without early intervention. Because the beta-chains are missing, the red cells become abnormal in shape and function. The spleen, which could be considered the filter of the red cells, removes all the abnormal red cells, thus producing a severe anemia that could not be compatible with life if not treated with frequent transfusions. The spleen may eventually get larger causing further anemia, abdominal pain and discomfort.

The bone marrow reacts by trying to produce more red cells to compensate for those removed. This leads to the expansion of the bone marrow spaces causing thinning of the covering bones and giving the characteristic leonine facial feature of kids with this disease. It also affects the growth of affected children. Transfusions, although life-saving, eventually lead to iron overload causing significant failure of different organs, such as the liver, heart and pancreas, because of the deposition of the extra-iron into those organs.

LIFE EXPECTANCY

In the past, the life expectancy of persons with Cooley’s anemia was usually into the 20s. Today, patients using iron binding (chelation) methods, with intravenous or, more recently tablets, can look forward to a longer and very productive life. The bound iron is eliminated through the urine. Recently, bone marrow transplantation has also been used successfully to treat this situation.

Cases of thalassemia minor are much more frequent. Patients with this condition will have a mild anemia. The inheritance is from only one parent. They are usually discovered by the routine blood tests that their physician would order. People with this “minor” type will live an otherwise normal life. The importance in their case is mostly genetic: People with this condition have a 50 percent chance of transmitting the deficient gene to their children. And if two people with the same disease procreate, there is a 25 percent risk that the progeny will have the “major” type in addition to a 50 percent chance of the “minor” form transmission. So, from a practical standpoint, people with the minor form need mostly genetic counseling.

It is important for our community to be aware of this disease because of its frequency and the health consequences related to it (social, financial, economical and psychological).

For more information on thalassemia call the Staten Island Chapter of the Cooley’s Anemia Foundation at 718-761-5380 or visit http://www.thalassemia.org.

This column is provided by the Richmond County Medical Society. Dr. Terenig Terjanian, is a longtime member of the Society. He specializes in hematology and oncology and is chairman of the Cancer Committee at Staten Island University Hospital.

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