Thallasemia is an inherited form of anemia, wherein there is a defect in the synthesis of hemoglobin. Thalassemia is an inherited disorder. It is sometimes called Mediterranean anemia, von Jaksch anemia or Cooley's anemia, named after the physicians who first diagnosed it. As a result of the decreased production of hemoglobin, the RBCs are small.
Thalassemia is a term that refers to a group of genetic disorders characterized by insufficient production of hemoglobin.
Thalassemia can show up in any population of people.
These conditions cause varying degrees of anemia, which can range from insignificant to life threatening. Thalassemia is actually a group of inherited diseases of the blood that affect a person's ability to produce hemoglobin, resulting in anemia. Genes involved are those that control the production of proteins known as globins, contained in hemoglobin. Hemoglobin production involves two sets of genes on different chromosomes which produce two different pairs of proteins. In people with thalassemia, the genes that code for hemoglobin are missing or variant (different than the normal genes).
Both types of thalassemia are inherited in the same manner. In beta thalassemia major (ie, homozygous beta thalassemia), the production of beta-globin chains is severely impaired, because both beta-globin genes are mutated. The disease is passed to children by parents who carry the mutated thalassemia gene. A child who inherits one mutated gene is a carrier, which is sometimes called "thalassemia trait." Most carriers lead completely normal, healthy lives. The blood cells are vulnerable to mechanical injury and die easily. To survive, many people with thalassemia need blood transfusions at regular intervals. Alpha thalassemia occurs when one or more of the four genes needed for making the alpha globin chain of hemoglobin are variant or missing. Moderate to severe anemia results when more than two genes are affected. A child who inherits two copies of the mutated gene for beta thalassemia will have beta thalassemia disease. The child can have a mild form of the disease, known as thalassemia intermedia, which causes milder anemia that rarely requires transfusions.
Thalassemia is an inherited disorder. Hemoglobin production involves two sets of genes on different chromosomes which produce two different pairs of proteins. One set is alpha, the other is beta. In beta thalassemia minor (ie, beta thalassemia trait or heterozygous carrier-type), one of the beta-globin genes is defective. The defect can be a complete absence of the beta-globin protein (ie, beta-zero thalassemia) or a reduced synthesis of the beta-globin protein (ie, beta-plus thalassemia) (see Image 1 ). The two main types of thalassemia, alpha and beta, are named for the two protein chains that make up normal hemoglobin. The most severe form of alpha thalassemia, which affects mainly individuals of Southeast Asian, Chinese and Filipino ancestry, results in fetal or newborn death. If one of the beta globin genes fails, the amount of beta globin in the cell is reduced by half; this condition is called thalassemia minor also called alpha-thalassemia and thalassemia minima. Infants become pale and listless, have a poor appetite, grow slowly, and often develop jaundice (yellowing of the skin). The spleen, liver, and heart may also be enlarged. Adolescents with the severe form may experience delayed puberty. The severity of illness depends on whether one or both genes are affected and the nature of the abnormality. If both genes are affected, anemia can range from moderate to severe.
Alpha thalassemia tends to be more common in people with the following ancestry:
- Middle Eastern
- East Indian
- Southeast Asian (Vietnamese, Laotian, Thai, Singaporean, Filipino, Cambodian, Malaysian, Burmese and Indonesian)
- Occasionally Mediterranean (Italian and Greek)
Beta thalassemia tends to be more common in people with the following ancestry:
- Mediterranean (Italian and Greek)
- Southeast Asian
E Beta thalassemia tends to be more common in people with the following ancestry:
- Southeast Asian (Cambodian, Vietnamese and Thai)
Sickle Beta Thalassemia tends to be more common in people with the following ancestry:
- Mediterranean (Italian, Greek and Turk)
Types of Thallasemia
1. Thallasemia major in which the defective gene is inherited from both parents. Those with thalassemia intermedia fluctuate between being asymptomatic and having symptoms as severe as those associated with thalassemia major. Diagnosis of thalassemia intermedia is usually made after a period of observation; the decision to transfuse is often a complex one.
2. Thallasemia minor where the defective gene is inherited from one parent and the other is
Diagnosis of thalassemia major is confirmed by Hemoglobin electrophoresis with an increase in total hemoglobin, and analysis of lymphocyte DNA.
Causes of Thallasemia
The common Causes of Thallasemia :
- The level of expression of fetal Hb (ie, the expression level of the gamma-globin gene) determines, in part, the severity of the disease.
- Patients with co-inheritance of alpha thalassemia have a milder clinical course because they have a less severe alpha-beta chain imbalance.
- Thalassemia is an inherited disease it is passed on from parents to their child through their genes.
- It tends to be found in individuals whose families come from the Mediterranean region, Africa, and sometimes Asia.
- Genetic and molecular studies on one case of alpha-thalassemia, found in Moscow region, have demonstrated that the cause of the disease is the deletion of 3 of 4 alpha-globin genes, presenting in the human diploid genome.
- The coexistence of sickle cell trait and beta thalassemia is a major and symptomatic hemoglobinopathy with most of the symptoms and complications of sickle cell disease.
- Patients with high fetal Hb have milder disease.
Symptoms of Thallasemia
Some are common Symptoms of Thallasemia :
- Fatigue (feeling tired) and weakness
- Pale skin or jaundice (yellowing of the skin)
- Protruding abdomen, with enlarged spleen and liver
- Shortness of breath
- Spleen enlargement
- Reduced appetite
Treatment of Thallasemia
Repeated blood transfusions.
There is no treatment when asymptomatic. If splenomegaly (inflamed spleen) is present-depending upon severity-splenectomy may be required.
Overall, however, transfusion and desferoxamine therapy have increased the life expectancy of individuals with the most severe types of beta thalassemia major to the 4th or 5th decade. This can be expected to improve with time and increased developments in treatment, as well as for those with more mild forms of the disease. Here is the list of the methods for treating Thallasemia :
- Some pregnant patients with the beta thalassemia trait may develop concurrent iron deficiency and severe anemia; they may require transfusional support if not responsive to iron repletion modalities.
- Patients receiving transfusion therapy also require iron chelation with desferrioxamine.
- Inform patients that their condition is hereditary and that physicians sometimes mistake the disorder for iron deficiency.
- Regular blood transfusions may be required.
- In advaced disease this can be a permanent cure.
- They should get an annual flu shot and the pneumonia vaccine to help prevent infections.
- A recent development in transplantation involves using blood from the umbilical cord from a newborn baby.
- Those with severe thalassemia have a serious and life-threatening illness. They are treated with regular blood transfusions, iron chelation (ke-LAY-shun) therapy, and bone marrow transplants.
- Researchers are also studying other treatments, such as gene therapy and fetal hemoglobin.
Alpha thalassemia appears in people whose hemoglobin does not produce enough alpha protein. There are five types of alpha thalassemia:
- Silent Carrier
- Alpha Thalassemia Trait
- Hemoglobin H Disease
- Hemoglobin H - Constant Spring
- Alpha Thalassemia Major
Beta thalassemia appears in people whose hemoglobin does not produce enough beta protein. There are three types of beta thalassemia:
- Thalassemia minor or Thalassemia trait - In this condition the individual has smaller than normal red blood cells but generally has no health problems. Occasionally, those with this condition suffer from mild anemia.
- Thalassemia Intermedia - In this condition the lack of beta protein causes more severe anemia and other health problems commonly associated with Thalassemia major (bone deformities and enlarged spleen). These individuals need more regular transfusions but it is typically to improve life not for survival.
- Thalassemia Major or Cooley's Anemia - This is the most severe of the beta thalassemias. These individuals require regular blood transfusions and other medical treatment for survival.