Thalassemias are inherited blood disorders characterized by decreased hemoglobin production. Symptoms depend upon the sort and may vary from none to severe. Often there's mild to severe anemia (low red blood cells or hemoglobin). Anemia may result in feeling tired and pale skin. There can also be bone problems, an enlarged spleen, yellowish skin, and dark urine. Slow growth may occur in children. Thalassemias are genetic disorders inherited from an individual's parents. There are two main types, alpha thalassemia, and beta-thalassemia. The severity of alpha and beta-thalassemia depends on what percentage of the four genes for alpha globin or two genes for beta-globin are missing. Diagnosis is usually by blood tests including an entire blood count, special hemoglobin tests, and genetic tests. Diagnosis may occur before birth through prenatal testing.