33% in adults with transfusion dependent beta thalassemia as compared to placebo and was also associated with decreased ferritin levels (with no significant decreases in liver or cardiac iron levels). Beta thalassemia intermedia Patients with beta thalassemia intermedia require no transfusions or may require episodic blood transfusions during certain circumstances (infection, pregnancy, surgery). Patients with frequent transfusions may develop iron overload and require chelation therapy. Transmission is autosomal recessive; however, dominant mutations and compound heterozygotes have been reported. Genetic counseling is recommended and prenatal diagnosis may be offered. Beta thalassemia minor Patients with beta thalassemia minor are usually asymptomatic and are often monitored without treatment. Beta thalassemia minor may coexist with other conditions such as chronic hepatitis B, chronic hepatitis C, non-alcoholic fatty liver disease and alcoholic liver disease that, when combined or co-existing, may cause a person to have iron overload of the liver and more severe liver disease. Epidemiology The beta form of thalassemia is particularly prevalent among the Mediterranean peoples and this geographical association is responsible for its naming: thalassa (θάλασσα) is the Greek word for sea and haima (αἷμα) is the Greek word for blood. In Europe, the highest concentrations of the disease are found in Greece and the Turkish coastal regions. The major Mediterranean islands (except the Balearics) such as Sicily, Sardinia, Corsica, Cyprus, Malta and Crete are heavily affected in particular. Other Mediterranean peoples, as well as those in the vicinity of the Mediterranean, also have high incidence rates, including people from West Asia and North Africa. The data indicate that 15% of the Greek and Turkish Cypriots are carriers of beta-thalassaemia genes, while 10% of the population carry alpha-thalassaemia genes. Evolutionary adaptation The thalassemia trait may confer a degree of protection against malaria, which is or was prevalent in the regions where the trait is common, thus conferring a selective survival advantage on carriers (known as heterozygous advantage), thus perpetuating the mutation. In that respect, the various thalassemias resemble another genetic disorder affecting hemoglobin, sickle-cell disease. Incidence The disorder is more prevalent in certain ethnicities and age groups. Beta thalassemia is most prevalent in the "thalassemia belt" which includes areas in Sub-Saharan Africa, the Mediterranean extending into the Middle East and Southeast Asia. This geographical distribution is thought to be due to beta-thalassemia carrier state (beta thalassemia minor) conferring a resistance to malaria. In the United States, thalassemia's prevalence is approximately 1 in