Beta thalassemias ( thalassemias) are a group of inherited blood disorders. They are forms of thalassemia caused by reduced or absent synthesis of the beta chains of hemoglobin that result in variable outcomes ranging from severe anemia to clinically asymptomatic individuals. Global annual incidence is estimated at one in 100,000. Beta thalassemias are caused by mutations in the HBB gene on chromosome 11, inherited in an autosomal recessive fashion. The severity of the disease depends on the nature of the mutation. HBB blockage over time leads to decreased beta-chain synthesis.