Thalassemia

Thalassemia
Other names	Thalassaemia, Mediterranean anemia
Peripheral blood film from a person with delta-beta thalassemia
Pronunciation	/θælɪˈsiːmiə/
Specialty	Hematology
Symptoms	Feeling tired, pale skin, enlarged spleen, yellowish skin, dark urine[1]
Causes	Genetic (autosomal recessive)[2]
Diagnostic method	Blood tests, genetic tests[3]
Treatment	Blood transfusions, iron chelation, folic acid[4]
Frequency	280 million (2015)[5]
Deaths	16,800 (2015)[6]

Thalassemias are inherited blood disorders that result in abnormal hemoglobin.^[7] Symptoms depend on the type of thalassemia and can vary from none to severe.^[1] Often there is mild to severe anemia (low red blood cells or hemoglobin) as thalassemia can affect the production of red blood cells and also affect how long the red blood cells live.^[1] Symptoms of anemia include feeling tired and having pale skin.^[1] Other symptoms of thalassemia include bone problems, an enlarged spleen, yellowish skin, pulmonary hypertension, and dark urine.^[1] Slow growth may occur in children.^[1] Symptoms and presentations of thalassemia can change over time. Thalassemia is also known as Cooley's anemia or Mediterranean anemia.^{[citation needed]}

Thalassemias are genetic disorders.^[2] There are two main types, alpha thalassemia and beta thalassemia.^[7] The severity of alpha and beta thalassemia depends on how many of the four genes for alpha globin or two genes for beta globin are missing.^[2] Diagnosis is typically by blood tests including a complete blood count, special hemoglobin tests, and genetic tests.^[3] Diagnosis may occur before birth through prenatal testing.^[8]

Treatment depends on the type and severity.^[4] Treatment for those with more severe disease often includes regular blood transfusions, iron chelation, and folic acid.^[4] Iron chelation may be done with deferoxamine, deferasirox or deferiprone.^[4][9] Occasionally, a bone marrow transplant may be an option.^[4] Complications may include iron overload from the transfusions with resulting heart or liver disease, infections, and osteoporosis.^[1] If the spleen becomes overly enlarged, surgical removal may be required.^[1] Thalassemia patients who do not respond well to blood transfusions can take hydroxyurea or thalidomide, and sometimes a combination of both.^[10] Hydroxyurea is the only FDA approved drug for thalassemia. Patients who took 10 mg/kg of hydroxyurea every day for a year had significantly higher hemoglobin levels, and it was a well-tolerated treatment for patients who did not respond well to blood transfusions.^[11] Other known hemoglobin-inducers include thalidomide, but it has not been tested in a clinical setting. The combination of thalidomide and hydroxyurea resulted in hemoglobin levels increasing significantly in transfusion-dependent and non-transfusion dependent patients ^[12]

As of 2015, thalassemia occurs in about 280 million people, with about 439,000 having severe disease.^[13] It is most common among people of Greek, Italian, Middle Eastern, South Asian, and African descent.^[7] Males and females have similar rates of disease.^{[citation needed]} It resulted in 16,800 deaths in 2015, down from 36,000 deaths in 1990.^[6][14] Those who have minor degrees of thalassemia, in common with those who have sickle-cell trait, have some protection against malaria, explaining why sickle-cell trait and thalassemia are more common in regions of the world where the risk of malaria is higher.^[15] An estimated 1/3 of people with thalassemia have "non-transfusion dependent thalassemia" and do not depend on regularly continuing blood transfusions to survive.