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.

[6] The imbalance of alpha to beta globin chains leads to ineffective erythropoiesis, increased hemolysis, and deranged iron homeostasis.

[8] Some people with thalassemia are susceptible to health complications that involve the spleen (hypersplenism) and gallstones (due to hyperbilirubinemia from peripheral hemolysis).

[citation needed] Excess iron (from hemolysis or transfusions) causes serious complications within the liver, heart, and endocrine glands.

[10] Heart failure, growth impairment, diabetes and osteoporosis are life-threatening conditions which can be caused by beta thalassemia major.

[11] The main cardiac abnormalities seen as a result of beta thalassemia and iron overload include left ventricular systolic and diastolic dysfunction, pulmonary hypertension, valvulopathy, arrhythmias, and pericarditis.

[8] Other tissues in the body can also become sites of erythropoiesis, leading to extramedullary hematopoietic pseudotumors which may cause compressive symptoms if they occur in the thoracic cavity or spinal canal.

As with about half of all hereditary diseases,[19] an inherited mutation damages the assembly of the messenger-type RNA (mRNA) that is transcribed from a chromosome.

Beta thalassemia occurs most often in people of Italian, Greek, Middle Eastern, Southern Asian, and African ancestry.

[8] Skeletal changes associated with expansion of the bone marrow: All beta thalassemias may exhibit abnormal red blood cells; a family history is followed by DNA analysis.

In most cases the treating physician uses a clinical prediagnosis assessing anemia symptoms: fatigue, breathlessness and poor exercise tolerance.

[28] Beta thalassemia is a hereditary disease allowing for a preventative treatment by carrier screening and prenatal diagnosis.

[31] This screening procedure proved insensitive in populations of West African ancestry because of the indicators has high prevalence of alpha thalassemia.

[8] Hepatic and myocardial MRI is also used to quantify the iron deposition in target organs, especially the heart and liver, to guide therapy.

[8] Scientists at Weill Cornell Medical College have developed a gene therapy strategy that could feasibly treat both beta-thalassemia and sickle cell disease.

[40] On June 10, 2022, a U.S. federal advisory panel recommended that the FDA approve a gene therapy treatment for use with beta thalassemia.

[41] The manufacturer Bluebird bio charges $2.8 million in the United States for its one-time treatment Zynteglo (betibeglogene autotemcel).

[44][45] Exagamglogene autotemcel, sold under the brand name Casgevy, is a gene therapy for the treatment of transfusion-dependent beta thalassemia developed by Vertex Pharmaceuticals and CRISPR Therapeutics.

[8] Patients with hypersplenism are more likely to have a lower amount of healthy blood cells in their body than normal and reveal symptoms of anemia.

[2] The laparoscopic method requires longer operating time but a shorter recovery period with a smaller and less prominent surgical scar.

If it is unnecessary to remove the entire spleen a partial splenectomy may occur; this method preserves some of the immune function while reducing the probability of hypersplenism.

By having leucoreduced blood packets, the patient is at a lower risk to develop adverse reactions by contaminated white cells and preventing platelet alloimmunisation.

Washed red cells have been removed of plasma proteins that would have become a target of the patient's antibodies allowing the transfusion to be carried out safely.

These regular transfusions promote normal growth and physical activities, and suppress bone marrow hyperactivity and extramedullary hematopoiesis, helping shrink painful masses in some cases.

This unbound iron is toxic due to its high propensity to induce oxygen species and is responsible for cellular damage.

In patients with iron overload, it is reasonable to start chelation therapy if LIC is >5 mg Fe per gram dry weight (dw) or serum ferritin level is >800 ng/mL.

[8] The molecule binds to select transforming growth factor beta superfamily ligands to block SMAD2 and 3 signaling, thus enhancing erythroid maturation.

The major Mediterranean islands (except the Balearics) such as Sicily, Sardinia, Corsica, Cyprus, Malta and Crete are heavily affected in particular.

[8] This geographical distribution is thought to be due to beta-thalassemia carrier state (beta thalassemia minor) conferring a resistance to malaria.