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beta thalassemia

Epidemiology: - most common in persons from Mediterranean, Southeast Asia, India, Pakistan Genetics: deletion or dysfunction of one or both beta-globin genes 1) beta-thalassemia minor: a) one of the 2 beta globin genes is affected b) mild anemia 2) beta-thalassemia major a) both beta-globin genes are affected b) severe anemia 3) beta-thalassemia intermedia - heterozygotes of beta-thalassemia major & beta-thalassemia minor - anemia of intermediate severity Laboratory: 1) complete blood count (CBC) a) RBC count may be normal to high b) MCV may be very low (microcytosis) 2) peripheral blood smear - microcytosis - target cells 3) reticulocyte count: reticulocytosis 4) hemoglobin electrophoresis a) hemoglobin F increased b) hemoglobin A2 increased 5) iron studies a) serum ferritin is normal b) serum iron, TIBC & % transferrin saturation are normal 6) beta globin gene mutation 7) also see more-specific type a) thalassemia major b) beta thalassemia intermedia c) thalassemia minor Differential diagnosis: - iron deficiency: a) low serum ferritin b) RBC count low c) RDW high d) hemoglobin electrophoresis normal Complications: - pulmonary hypertension - inappropriate administration of iron for microcytic anemia may lead to iron overload* * iron overload can occur in patients with thalassemia without blood transfusion [2] Management: - folate supplementation

Interactions

disease interactions

Related

beta globin gene

Specific

beta thalassemia intermedia beta thalassemia major (Cooley's anemia) beta thalassemia minor; beta thalassemia trait hemoglobin S/beta thalassemia + hemoglobin S/beta thalassemia 0 hereditary persistence of hemoglobin F X-linked thrombocytopenia with beta-thalassemia; thrombocytopenia, platelet dysfunction, hemolysis, & imbalanced globin synthesis

General

thalassemia

References

  1. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 585-86
  2. Medical Knowledge Self Assessment Program (MKSAP) 14, 15, 16, 17, 18. American College of Physicians, Philadelphia 2006, 2009, 2012, 2015, 2018. - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  3. NEJM Knowledge+ Question of the Week. Jan 7, 2020 https://knowledgeplus.nejm.org/question-of-week/1071/ - Rund D, Rachmilewitz E. Beta-thalassemia. N Engl J Med 2005 Sep 16; 353:1135. PMID: 16162884 https://www.nejm.org/doi/full/10.1056/NEJMra050436
  4. Taher AT, Musallam KM, Cappellini MD beta-Thalassemias. N Engl J Med 2021; 384:727-743. Feb 25 PMID: 33626255 https://www.nejm.org/doi/full/10.1056/NEJMra2021838 - Rothaus C beta-Thalassemias NEJM REsident 360. FEb 24, 2021 https://resident360.nejm.org/clinical-pearls/thalassemias