Hematology
Thalassemia
Overview:
Thalassemia is an inherited blood disorder that causes your body to have less hemoglobin and fewer red blood cells than normal. 

Other Names:
Mediterranean Anemia

Types:
The type of thalassemia depends on the number of gene mutations and the affected part. The mutation occurs in one, or both, of the alpha/ beta hemoglobin molecules:
  1. ​Alpha-thalassemia: Four genes are involved in making the alpha hemoglobin chain (two from each of the parents). Mutated genes cause Alpha-Thalassemia which varies in severity according to mutation degree. If you inherit:  
    1. One mutated gene (alpha-thalassemia silent carrier), you will have no signs or symptoms of thalassemia. But you are a carrier of the disease and can pass it on to your children.
    2. Two mutated genes (alpha-thalassemia trait), your thalassemia signs and symptoms will be mild and sometimes unapparent, but can be detected with a blood test.
    3. Three mutated genes, your signs and symptoms will be moderate to severe. This condition is called Hemoglobin H disease as it causes severe anemia. Your blood test will show small, deformed red blood cells. You will develop an enlarged spleen and deformed bones, due to increased activity to replace damaged red blood cells. For a normal life, blood transfusions are often needed. 
    4. Four mutated genes (alpha-thalassemia major), this condition causes prenatal and neonatal mortalities.  
  2. Beta-thalassemia:
    1. Two genes are involved in making the beta hemoglobin chain. You get one from each of your parents. Mutated genes cause Beta-Thalassemia which varies in severity according to mutation degree: 
    2. Thalassemia Minor: If you inherit one mutated gene, you will have mild signs and symptoms. Routine blood tests will detect only mild anemia. 
    3. Thalassemia Major: If you inherit two mutated genes, your signs and symptoms will be moderate to severe: severe anemia, deformed bones and enlarged spleen. For a normal life, blood transfusions are often needed. Babies born with two defective beta hemoglobin genes usually are healthy at birth but develop signs and symptoms within the first two years of life.    

Causes:
Thalassemia is caused by mutations in the DNA of cells that make hemoglobin. The mutations associated with thalassemia are passed from parents to children, causing genetic mutations that reduce natural hemoglobin production. In thalassemia, lower levels of hemoglobin and higher rates of damaged red blood cells lead to symptoms of anemia.  

Risk Factors:
  • Family history of thalassemia.
  • Thalassemia occurs most often in people of Mediterranean (including Italy, Greece, Cyprus, and the Middle East), Indian, Pakistani, Bangladeshi, Chinese, and Southeast Asian descent. 

Symptoms:
  • Anemia
  • Fatigue
  • Weakness and shortness of breath
  • Irregular heartbeat (palpitations)
  • ​Pale or yellowish skin due to hemoglobin deficiency
  • Iron overload in the body due to frequent blood transfusions
  • Slow growth
  • Osteoporosis
  • Decreased fertility​
Complications:
  • Heart and liver diseases: People with thalassemia can get too much iron in their bodies, either from the disease or from frequent blood transfusions. Too much iron can result in damage to organs and tissues, especially heart and liver.  
  • Infection.
  • Osteoporosis.

Diagnosis:
  • Blood tests including Complete blood count (CBC).
  • Hemoglobin tests that measure types of hemoglobin in a blood sample.
  • Ferritin test that measures the amount of ferritin in blood to detect whether anemia is due to iron deficiency or thalassemia. 
  • Family genetic studies may also assist in the diagnosis of the disorder. Such studies include testing the medical history and blood samples of family members, detecting whether any of them have the lost or changed hemoglobin genes. 
  • Prenatal testing, including amniocentesis or chorionic villus sampling, to find out if the baby has thalassemia and determine how severe it might be.

Treatment:
Treatment of thalassemia depends on its type and severity. For moderate to severe thalassemia, treatments might include:
  • Blood transfusion
  • Folic acid supplements
  • Stem cell transplant
  • Treatment of complications

Prevention:

  • In most cases, you cannot prevent thalassemia, as it is hereditary (genetically passed on from parents to children). However, tests during pregnancy can detect such blood disorders before birth.
  • Family genetic studies may assist in detecting whether people have lost the hemoglobin genes that caused them to change. 
  • If you have thalassemia, or if you carry a thalassemia gene, consider talking with a doctor and genetic counselor for guidance if you want to have children. 

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Last Update : 07 February 2021 03:30 AM
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