Thalassemia or thalassaemia is an inherited autosomal recessive blood defect. In thalassemia, the genetic disorder causes decreased rate of synthesis of one of the globin chains that contitutes hemoglobin.fyh
The red blood cells contain an oxygen-carrying substance known as hemoglobin which makes blood red. The main purpose of hemoglobin is to combine with oxygen and transport it from the lungs and distribute it to all body tissues, where it is necessary to supply energy for the chemical reaction of all living cells.
Hemoglobin contains considerable amount of iron. When red blood cells are broken down, most of the iron from the hemoglobin is used again to produce new hemoglobin. In the case of thalassemia the hemoglobin is fragile and breaks down more easily than normal, thus leaving the person with not enough hemoglobin in their body. This lack of hemoglobin results in anemia.
This is a very acute blood disease that appears in early childhood. If thalassemia is left untreated, it usually takes life of children between one and eight years of age.
Children with thalassemia major are normal at birth but become anemic between the age of three months and eighteen months. They become pale, do not sleep well, do not want to eat, and may vomit frequently after feedings.
Thalassemias affect both males and females. It is very common mainly among people of Italian, Greek, Middle Eastern, Asian, and African origin. Severe forms of thalassemia are usually detected in early childhood and are lifelong conditions.
What Causes Thalassemias?
Your body produces 3 types of blood cells: red blood cells, white blood cells, and platelets (PLATE-lets). Red blood cells contain hemoglobin, a protein which is rich in iron and transports oxygen from your lungs to all parts of your body. Hemoglobin also takes carbon dioxide (a waste gas) from your body to your lungs to be breathed out.
Hemoglobin consists of 2 kinds of protein chains: alpha globin and beta globin. If your body doesn\’t produce sufficient amount of these protein chains, red blood cells don\’t form correctly and can\’t carry enough oxygen. Your body won\’t work properly if your red blood cells are unable to produce enough healthy hemoglobin.
Genes control the production of protein chains by hemoglobin. When these genes are not present or altered, thalassemias take place.
Thalassemias are hereditary diseases as they\’re transmitted from parents to their next generation through genes. People who inherit abnormal hemoglobin genes from one parent but normal genes from the other are usually carriers who often show no symptoms of illness except mild anemia. However, they can transmit the abnormal genes on to their offspring.
People with moderate to harsh kinds of thalassemia usually inherit abnormal genes from both of their parents.
Alpha Thalassemias
Four genes (two from each parent) are required to produce sufficient alpha globin protein chains. If one or more of the genes is absent, you will acquire alpha thalassemia. This indicates that you don\’t produce sufficient alpha globin protein.
If you contain only one missing gene, you\’re not a prominent carrier and won\’t have any symptoms of illness.
If you have two missing genes, you have alpha thalassemia trait (also called alpha thalassemia minor). You may have mild anemia.
If you have 3 missing genes, you will probably have hemoglobin H which can be detected by a blood test. This type of thalassemia causes moderate to severe anemia.
Very often, all four genes may be missing and such condition is known as alpha thalassemia major or hydrops fetalis. Babies suffering from hydrops fetalis usually expire before or right after birth.
Beta Thalassemias
Beta-thalassemia, the most known form of the disorder falls into 3 categories: beta-thalassemia minor (trait), intermedia, and major (Cooley\’s anemia).
Two genes (one from each parent) are required to produce sufficient amount of beta globin protein chains. If one or both of these genes are changed, you will be afflicted by beta thalassemia and this denotes that you produce adequate beta globin protein.
If you possess single altered gene, you\’re surely a carrier. This condition is identified as beta thalassemia trait or beta thalassemia minor. It also brings about mild anemia. If both genes are altered, you will have beta thalassemia intermedia or beta thalassemia major, also termed as Cooley\’s anemia. Thalassemia intermedia results in moderate anemia. The major form of the disease causes severe anemia.
Family history and ancestry are the 2 risk factors associated with thalassemias.
Alpha thalassemias are very common in Southeast Asian, Indian, Chinese, or Filipino origin or ancestry.
Beta thalassemias commonly occur to people of Mediterranean (Greek, Italian, and Middle Eastern), Asian, or African origin or ancestry.
Symptoms of Severe Anemia or Beta Thalassemia major
PalenessPeople with thalassemia major may have the following:
- Headaches
- Fatigue
- Shortness of breath
- Jaundice
- Spleen enlargement
- Poor appetite
- Dark urine
- Bone problems (especially bones in the face)
Mild to Moderate Anemia
People with beta thalassemia intermedia experience mild to moderate anemia. They also may experience other health problems, like:
Slowed growth and delayed puberty: Anemia can delay a child\’s growth and maturity.
Bone problems: Thalassemia may also expand bone marrow (the spongy material inside bones that produces blood cells). This is actually responsible for wider bones than normal. Bones also may become brittle and break simply.
An enlarged spleen: The spleen helps your body combat infection and removes useless material. When a person is inflicted by thalassemia, the spleen should work efficiently. Consequently, the spleen becomes larger than normal. This aggravates anemia. In case the spleen becomes too large, it must be eliminated.
Alpha thalassemia—No symptoms
Alpha thalassemia silent carriers generally show no signs or symptoms of the disease. This is primarily because of the lack of alpha globin protein which is so little that hemoglobin works as usual.
Diagnosis of thalassemia
Doctors diagnose thalassemias using blood tests, including a Complete Blood Count (CBC) and special hemoglobin tests.
A CBC measures the amount of hemoglobin and different types of blood cells, like red blood cells, in a sample of blood. People having thalassemias have fewer healthy red blood cells and less hemoglobin in their blood than normal. People who suffer from alpha or beta thalassemia trait may possess lower than normal red blood cells.
Hemoglobin tests calculate the types of hemoglobin in a blood sample. People suffering from thalassemias have troubles with the alpha or beta globin protein chains of hemoglobin.
Moderate and severe thalassemias are normally diagnosed in early childhood. This is due to signs and symptoms, including severe anemia that may appear within the first 2 years of life.
As thalassemias are transmitted from parents to children, family genetic studies also can contribute to diagnose the disease. This involves taking a family medical history and performing blood tests on family members to find out if anyone have missing or altered hemoglobin genes.
If you\’re pregnant and you and your partner are thalassemia carriers, you may need prenatal testing.
Treatments
Treatments for thalassemias are based on the type and severity of the disorder. There are 3 standard treatments assorted for moderate and severe forms of thalassemia including blood transfusions, iron chelation (ke-LAY-shun) therapy, and folic acid supplements. Other treatments have been developed or are being tested, but they\’re used occasionally.
Blood Transfusions
A blood transfusion, applied through a needle in a vein, offers you healthy red blood cells with normal hemoglobin. Red blood cells exist for only about 120 days. So, you may require frequent transfusions in order to keep up a supply of healthy red blood cells.
If you have hemoglobin H disorder or beta thalassemia intermedia, you may require blood transfusions sometimes. If you have beta thalassemia major, or Cooley\’s anemia, you will be in need of regular blood transfusions (often every 2 to 4 weeks). These will play a crucial role in retaining normal hemoglobin levels and red blood cell count. Blood transfusions are lifesaving, but they\’re costly too and there always lies a risk of transmitting infections and viruses (for instance, hepatitis).
Iron Chelation Therapy
Daily blood transfusions can bring about development of iron in the blood. This situation is called iron overload. It affects the liver, heart, and other parts of the body.
In order to prevent this damage, iron chelation therapy is required to remove surplus iron from the body. Two medicines are referred for iron chelation therapy.
Deferoxamine is a liquid medicine. It is given slowly under the skin, normally with a little portable pump used overnight. This therapy requires time and can be slightly painful. Side effects of this therapy include loss of vision and hearing.
Deferasirox is a pill taken once a day. The side effects of this pill comprise headache, nausea (feeling sick to the stomach), vomiting, diarrhea, joint pain, and fatigue (tiredness).
Folic Acid Supplements
Folic acid is a B vitamin that helps build healthy red blood cells. You may need to take folic acid supplements along with blood transfusions and/or iron chelation therapy.
Prevention
1. As Thalassemias are hereditary (i.e. passed on from parents to children) they can\’t be prevented. However, these bleeding disorders can be detected prior to birth through few prenatal tests.
2. Family genetic studies may be helpful to find out whether people have missing or altered hemoglobin genes that are responsible for thalassemias.
3. If you are aware of your family members having thalassemias and you\’re thinking of having children, have a chat with your doctor and/or a genetic counselor. They can help make you aware of your risk for transmitting the disorder to your child.