Reduces the production of hemoglobin. 
Thalassemia is a blood disorder passed down through families (inherited) in which the body makes an abnormal form of hemoglobin, the protein in red blood cells that carries oxygen. The disorder results in excessive destruction of red blood cells, which leads to anemia. Thalassemia is a group of inherited blood disorders that affect the body's ability to produce hemoglobin and red blood cells-patients have a lower-than-normal number of red blood cells in their bodies and too little hemoglobin. In many cases the red blood cells are too small. Our red blood cells carry Causes. Thalassemia is caused by mutations in the DNA of cells that make hemoglobin — the substance in your red blood cells that carries oxygen throughout your body. The mutations associated with thalassemia are passed from parents to children. Thalassemia occurs when there is a defect in a gene that helps control production of one of these proteins. There are two main types of thalassemia: 1  Alpha thalassemia occurs when a gene or genes related to the alpha globin protein are missing or changed (mutated). Thalassemia is a blood disorder passed down through families (inherited) in which the body makes an abnormal form of hemoglobin. Hemoglobin is the protein in red blood cells that carries oxygen. The disorder results in large numbers of red blood cells being destroyed, which leads to anemia. Alpha thalassemia occurs when there is a problem with the alpha-globin part of hemoglobin. Beta thalassemia occurs when there is a problem with the beta-globin part of hemoglobin. There are both mild and severe forms of alpha and beta thalassemia. Severe beta thalassemia is often called Cooley's anemia. Thalassemia is an inherited disorder that affects the production of normal hemoglobin (a type of iron-rich protein in red blood cells that carries oxygen to the tissues of the body). Thalassemia includes a number of different forms of anemia, which are classified as either alpha thalassemias or beta thalasemias. Beta thalassemia is a blood disorder that reduces the production of hemoglobin. Hemoglobin is the iron-containing protein in red blood cells that carries oxygen to cells throughout the body. The mutations that cause thalassemia disrupt the normal production of hemoglobin and cause low hemoglobin levels and a high rate of red blood cell destruction, causing anemia. When you're anemic, your blood doesn't have enough red blood cells to carry oxygen to your tissues — leaving you fatigued.
http://www.healthline.com/health/thalassemia http://www.medicalnewstoday.com/articles/263489.php http://www.mayoclinic.org/diseases-conditions/thalassemia/basics/causes/con-20030316 https://www.nlm.nih.gov/medlineplus/ency/article/000587.htm https://www.nlm.nih.gov/medlineplus/ency/article/000587.htm http://blood.emedtv.com/thalassemia/causes-of-thalassemia.html http://www.hopkinsmedicine.org/healthlibrary/conditions/hematology_and_blood_disorders/beta_thalassemia_cooleys_anemia_85,P00081/ http://ghr.nlm.nih.gov/condition/beta-thalassemia http://www.mayoclinic.org/diseases-conditions/thalassemia/basics/causes/con-20030316
what is the cause of thalassemia