Thalassemia is an inherited blood disorder that is manifested in several different forms. All forms of thalassemia are due to defective genes inherited from either parent or both parent. Broadly, thalassemia can be classified as major and minor. Those who have inherited the defective gene that controls the process of globin production from one parent have thalassemia minor. They may not have symptoms of the disease and may have a lower than normal blood count, but they carry the trait of the disease and can pass it on to their progeny. Those who inherit a defective gene each from both parents have thalassemia major.
A complete blood count test reveals smaller than normal red blood cells even in those who have the thalassemia trait with only one defective alpha globin gene or beta globin gene. The number of healthy red blood cells is less than normal, and the hemoglobin content of the blood is lower in the case of those who have thalassemia. People with anemia are tested for thalassemia since the anemia is likely to be due to a missing or a defective alpha or beta globin gene.
Doctors may order thalassemia tests for a child with anemia if the child belongs to an ethnic population that is known to be susceptible to thalassemia. Hemoglobin electrophoresis is used to test the haemoglobin for abnormal forms. A mutational analysis may be carried out when alpha thalassemia is suspected but is not confirmed by the haemoglobin electrophoresis test.
Most children with thalassemia major appear normal at birth, but symptoms appear by the first year. Slow growth, pale skin, and a bulging abdomen caused by an enlarged spleen are seen along with anemia.
All forms of thalassemia are inherited. A person with a mutated or defective gene may be a carrier of the disease without exhibiting any symptoms. It must, however, be understood that a thalassemia minor cannot progress into a thalassemia major. Another classification of thalassemia is based on the protein types that make up the haemoglobin in the blood cells: the alpha globin and the beta globin. We get two genes from each parent to make the alpha globin protein chains. To make beta globin protein chains we inherit one gene from each parent. A gene defect or mutation that affects the production of either of their protein chains can result in alpha thalassemia or beta thalassemia.
An enlarged spleen is a typical symptom in patients with thalassemia. Since the spleen is actively involved in empowering the body's immune system and in the destruction and recycling of old and abnormal red blood cells, it has to work doubly hard in thalassemia patients. Anemia is another symptom that is common to all forms of thalassemia. Fatigue and shortness of breath due to the insufficient oxygen supply to the tissues of the body are other symptoms noticed. Thalassemia symptoms in adults, children, and women are more or less the same.
Alpha thalassemia is silent in those who have just one defective inherited gene out of the four required to make the alpha globin. Those with two defective genes have the alpha thalassemia trait and may be anemic, but may not have other symptoms. When all four of the genes are defective, it results in Hb Bart Syndrome or hydrops fetalis, which is characterized by fluid build-up in the body of the fetus before birth. Babies with this condition are stillborn or die shortly after birth. HbH disease affects those who have three defective alpha globin genes, and these people may have lifelong haemolytic anemia and splenomegaly, besides brittle and weak bones. Those who have inherited only one defective gene out of the two needed to make beta globin are carriers of beta thalassemia. Patients with mild beta thalassemia may experience delayed growth and puberty due to anemia. Weak and brittle bones and facial bone disfigurements are seen in those with beta thalassemia major. Beta thalassemia major is also sometimes referred to as Cooley's anemia.
People who have the thalassemia trait usually do not exhibit any symptoms other than anemia and may not need any treatment. In fact, many are not even aware of being carriers until a blood test establishes the fact, unless they are aware of their family medical history. Children with any form of thalassemia need to be monitored with yearly health check- ups for their physical growth and development. Blood transfusions to infuse healthy red blood cells into the body are the usual treatment for those with thalassemia major. However, this treatment may be needed at regular intervals for those with Cooley's anemia.
Transfusions are resorted to only if they are necessary and care is taken to stop iron supplements in such cases. Blood screening is vital to ensure that the patient does not get other infections due to the transfusion. The disadvantage of this treatment is that it may lead to an iron overload in the blood. This build-up of iron can damage vital organs like the liver and the heart. Medication taken to remove this excess iron can have unpleasant side effects like nausea and joint pain. Folic acid supplements are given to boost the production of healthy red blood cells in the body. People with enlarged spleens may get them removed to prevent a fatal rupture of the spleen. However, without the spleen, they become susceptible to infections and need to be very careful and get all the necessary vaccinations done. A bone marrow stem cell transplant from a suitable donor can replace the defective stem cells in the bone marrow with healthy cells so that normal red blood cell production results. This is a cure for thalassemia provided a matched donor can be found in time for the procedure.
Prevention of thalassemia is possible when couples get themselves tested before starting a family. Even if one of them is a carrier, based on the family histories, a genetic counsellor can help determine the risks that are involved. Prenatal tests are also conducted to check for thalassemia and other blood disorders before birth.