beta thalassemia fact sheet - bristol-myers squibbbeta thalassemia is usually inherited in an...
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1 NIH US National Library of Medicine. Genetics Home Reference: Beta thalassemia. Available at: https://ghr.nlm.nih.gov/condition/beta-thalassemia. Accessed November 2019. 2 National Center for Advancing Translational Sciences, Genetic and Rare Diseases Information Center. Beta-thalassemia. Available at: http://rarediseases.info.nih.gov/gard/871/beta-thalassemia/resources/1. Accessed November 2019. 3 Cao A, Galanello R. Beta-thalassemia. Genetics in Medicine. 2010;12:61–76. Available at: http://www.nature.com/gim/journal/v12/n2/full/gim201012a.html?foxtrotcallback=true. Accessed November 2019. 4 Galanello R, Origa R. Beta-thalassemia. Orphanet Journal of Rare Diseases. 2010;5(11). Available at: https://ojrd.biomedcentral.com/articles/10.1186/1750-1172-5-11. Accessed November 2019. 5 National Organization of Rare Disorders. Available at: https://rarediseases.org/rare-diseases/thalassemia-major/. Accessed November 2019. 6 NIH US National Library of Medicine. Genetics Home Reference: HBB gene. Available at: https://ghr.nlm.nih.gov/gene/HBB#normalfunction. Accessed November 2019. 7 Muncie Jr HL, Campbell J. Alpha and beta thalassemia. Am Fam Physician. 2009; 80(4):339-344. Available at: https://www.ncbi.nlm.nih.gov/pubmed/19678601. Accessed November 2019. 8 NIH Heart Lung and Blood Institute. How Are Thalassemias Diagnosed? Available at: https://www.nhlbi.nih.gov/health/health-topics/topics/thalassemia/diagnosis. Accessed November 2019. 9 Mayo Clinic. Enlarged spleen (splenomegaly). Available at: https://www.mayoclinic.org/diseases-conditions/enlarged-spleen/diagnosis-treatment/drc-20354331.
Accessed November 2019.10 Mayo Clinic. Thalassemia. Available at: https://www.mayoclinic.org/diseases-conditions/thalassemia/symptoms-causes/syc-20354995.
Accessed November 2019.11 Cappellini MD, Cohen A, Eleftheriou A, et al. Guidelines for the Clinical Management of Thalassaemia.
Available at: https://www.ncbi.nlm.nih.gov/books/NBK173970/. Accessed November 2019.
BETA THALASSEMIAMECHANISM OF DISEASE Beta thalassemia is a rare, inherited blood disorder characterized by low levels of hemoglobin, which resides in red blood cells and carries oxygen throughout the body.1
This leads to:1,2
Beta thalassemia is often classified into three types:2,3,4
MAJORLeads to severe anemia and may cause enlarged liver and spleen, resulting in a need for regular blood transfusions
MINORCarriers are typically asymptomatic, but may have mild anemia
Production of fewer and less healthy red blood cells
Potential to develop severe anemia
Other serious symptoms, such as abnormal blood clots
INTERMEDIACauses mild to moderate anemia and mayhave variable transfusion needs; some patients may need more transfusions as they age
Most beta thalassemia cases are caused by
a mutation in the hemoglobin subunit
beta (HBB) gene, which provides instructions for
making beta-globin.5,6
Two alpha- and two beta-globin protein chains combine to form hemoglobin.6
Significantly reduced levels of beta chains – presenting as
beta thalassemia intermedia
Beta chains
Alpha-globin protein chains
An almost complete lack of beta chains – presenting as
beta thalassemia major
The reduction or lack of beta-globin protein chains leads to an imbalance with the alpha-globin protein chains,resulting in the abnormal formation of red blood cells, a lack of functional hemoglobin and the failure to deliver sufficient amounts of oxygen to the body
HOW IT DEVELOPS
A mutation in two HBB genes can result in either:5
Beta thalassemia occurs most frequently in people from Mediterranean countries, North Africa, the Middle East, India, Central Asia and Southeast Asia1
BUT HAS A GROWING PREVALENCE WORLDWIDEdue to population migration and intermarriage between different ethnic groups4
KEY STATISTICS
BETA THALASSEMIA AFFECTS MEN AND WOMEN EQUALLY7
1.5%have the GENETIC MUTATION that causes one of three types
of beta thalassemia4
80-90 MILLION PEOPLE
GL BALLY
DIAGNOSIS AND SYMPTOMS
GENETIC TESTS
BLOOD TESTS, INCLUDING A COMPLETE BLOOD COUNT AND SPECIAL HEMOGLOBIN TESTS
Anemia Bone and muscle
abnormalities
Abnormalitiesof the spleen,
liver and heart
Growth deficiencies
Cardiac complications (pulmonary hypertension, arrhythmia, thrombosis)
Hepatic and endocrine
complications
Testing includes:8
Symptoms are often dependent on treatment and disease severity, including:2,3
Beta thalassemia is usually inherited in an autosomal recessive manner, which means both copies of the HBB gene in each cell have mutations.5 Healthcare professionals typically look at a person’s medical history, symptoms, physicalexam and laboratory test results in order to make a diagnosis.5 Beta thalassemia major is often diagnosed in children under the age of two.1
DISEASE MANAGEMENT
PROGNOSIS
SUPPLEMENTATIONwith folic acid, a B vitamin, boosts the production of red blood cells in certainindividuals.5 B9
Individuals with beta thalassemia MAJOR and some with beta thalassemia INTERMEDIA
as frequently as
weeks in severe cases52-4 EVERY
REQUIRE REGULAR BLOODTRANSFUSIONS
TREATMENT COMPLICATIONS & MANAGEMENT
STEM CELLTRANSPLANT
FOLIC ACID, ALONG WITH OTHER MEDICATIONS, MAY HELP LOWER IRON LEVELS.5
Most common for patients
<16 years of age and/or those with an appropriate match5
can cause severe pain and contribute to anemia5
Splenomegaly may occur due to increased destruction of red blood cells, the formation of blood cells outside of the bone marrow (extramedullary hematopoiesis) or repeated blood transfusions5
Treatment of splenomegaly is often focused on the underlying cause, and may include:9
(an abnormally enlarged spleen)SPLENOMEGALY
Individuals with beta thalassemiaMAJOR AND INTERMEDIA
may develop IRON OVERLOAD, which can affect other organs5
Iron overload is most often managed by iron chelation therapy, which rids the body of extra iron4
Watchful waiting Antibiotics
Radiation Surgical removal (splenectomy)
As a side effect of blood transfusions
Due to increasedabsorption of dietary iron by the gastrointestinal tract
This occurs for TWO reasons:5
Advances in red blood cell transfusions have further prolonged survival in recent years. However, there continue to be very limited options for patients living with anemia due to beta thalassemia who are dependent on long term red blood cell transfusions.4
may be associated with severe beta thalassemia and can impact a patient’s survival.3,10
In more advanced stages, heart and liver problems such as congestive heart failure, abnormal heart rhythms (arrhythmias) and liver fibrosis
With proper disease managementpatients can enjoy a near-normal lifestyle, and can experience normal physical and
emotional development from childhood to adulthood, including parenthood.11