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تعداد آیتم قابل مشاهده باقیمانده : 3 مورد
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Classical thalassemia syndromes (genotypes and laboratory findings)

Classical thalassemia syndromes (genotypes and laboratory findings)
Syndrome Genotype Typical findings on CBC Hemoglobin analysis
(HPLC or other protein chemistry method)
Alpha thalassemias (reduction in alpha globin chains)
Alpha thalassemia major (ATM) (– – / – –) Severe microcytic anemia with hydrops fetalis; usually fatal in utero Hb Barts (γ globin tetramers); Hb Portland (embryonic hemoglobin); no Hb F, Hb A, or Hb A2
Hb H disease

(α – / – –)

or

(α αt / – –)*
Moderate microcytic anemia Hb H (up to 30%); Hb A2 (up to 4%)
Alpha thalassemia minor (also called alpha thalassemia trait)

(α – / α –)

or

(α α / – –)
Mild microcytic anemia Hb Barts (3 to 8%, only in the newborn period)
Alpha thalassemia minima (also called silent carrier) (α α / α –) Normal or mildly decreased hemoglobin, normal or mildly decreased MCV Normal
Beta thalassemias (reduction in beta globin chains)
Transfusion-dependent (TDT, previously called beta thalassemia major)

β0 / β0

or

β0 / β+
Severe microcytic anemia with target cells (typical Hb 3 to 4 g/dL) Hb A2 (5% or more); Hb F (up to 95%); no Hb A
Non-transfusion-dependent (NTDT, previously called beta thalassemia intermedia)

β+ / β+

or

β0 / β+

or

Coinheritance of other variantsΔ
Moderate microcytic anemia Hb A2 (4% or more); Hb F (up to 50%)
Beta thalassemia minor (also called trait or carrier)

β / β0

or

β / β+
Mild microcytic anemia Hb A2 (4% or more); Hb F (up to 5%)
This table lists classical thalassemia syndromes; numerous other combinations and phenotypes are possible. Refer to UpToDate topics on thalassemia genetics, pathophysiology, and diagnosis for more details.

CBC: complete blood count; HPLC: high-performance liquid chromatography; Hb: hemoglobin; Hb F: fetal hemoglobin; Hb A: adult hemoglobin; MCV: mean corpuscular volume; TDT: transfusion-dependent beta thalassemia; NTDT: non-transfusion-dependent beta thalassemia.

* The "t" stands for an alpha globin with a structural mutation that can result in very low hemoglobin output (usually 1 to 10%), such as Hb constant spring (α αcs / – –) causing a more severe phenotype than (α – / – –). Other Hb H disease genotypes are possible such as t / α –) or t / αt –).

β0 refers to no beta globin production; β+ refers to decreased beta globin production; Hb E is a β+ mutation.

Δ Other variants that can be seen in NTDT include Hb E (in combination with heterozygosity for a beta thalassemia variant), hereditary persistence of fetal hemoglobin (HPFH; in combination with homozygous beta thalassemia), alpha thalassemia (in combination with homozygous β+ thalassemia), or triplicated or quadruplicated alpha genes (αα / ααα or αα / αααα; in combination with heterozygous beta thalassemia). Dominantly acting beta thalassemia variants can also occur.
Prepared with data from: Brancaleoni V, Di Pierro E, Motta I, Cappellini MD. Laboratory diagnosis of thalassemia. Int J Lab Hematol 2016; 38 Suppl 1:32.
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