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Thalassemia and Sickle Cell Hemoglobinopathy

  1. Embryonic Hgb
    • 2 Zeta Chains &
    • 2 Beta, 2 Gamma, or 2 Delta Chains
  2. Fetal Hgb
    • 2 Alpha Chains
    • 2 Gamma Chains
  3. Adult Hgb A1
    • 2 Alpha Chains
    • 2 Beta Chains
  4. Adult Hgb A2
    • 2 Alpha Chains
    • 2 Delta Chains
  5. Normal Hgb Distribution
    • Hgb A1 96%
    • Hgb A2 2-3%
  6. Abnormal Hgb Fractions
    • Hgb S
    • Hgb C
    • Hgb H
    • Hgb E
    • Hgb M
    • Bart's Hgb
  7. Abnormal Structures due to?
    Amino acid substitutions on globin chains.
  8. Types of abnormal structures.
    • Sickle Cell Anemia
    • Sickle Cell Trait
    • Hgb C Disease
    • Hgb S-C Disease
  9. Abnormal Synthesis
    • Due to manufactor of Alpha or Beta Chains
    • Alpha Thalassemia
    • Beta Thalassemia
  10. Hgb S
    • #6 Amino Acid on beta chains is replaced with Valine.
    • Inherited as Autosomal recessive gene.
    • Homozygous is SS
    • Heterozygous is AS
  11. Hgb C
    • #6 Amino Acids on beta chains replaced with lysine.
    • Inherited with Autosomal recessive gene.
    • Homozygous state 93-100% Hgb C
    • Commonly inherited in combination with Hgb S
  12. Hgb E
    • Lysine substituted for #26 amino acid on beta chains.
    • Autosomal recessive.
    • Homozygous Hgb E is microcytic anemias with target cells.
    • Heterozygous is silent carrier.
    • 30% of southeast asians have Hgb E.
  13. Hgb M
    • Tyrosine is substituted for histadine on either Beta or Alpha Chains.
    • Hgb M is methomoglobin (Fe + 3)
    • Autosomal Dominant
    • Patient Appears Cyanotic
    • Blood Appears Brown.
    • Heinz Bodies Present.
  14. Hgb H
    4 beta chains
  15. Bart's Hgb
    Globin structure is 4 gamma chains.
  16. Hereditary Persistance of fetal Hgb (HPFH)
    • Continued production of Hgb F into adulthood.
    • Homozygous 100% Hgb F
    • Heterozygous 30% Hgb F
  17. Detection of Hgb S
    • Abnormal RBC Morphology on smear.
    • Positive screening method.
    • Confirm with electrophoresis.
  18. Sickle Cell Anemia
    • Normocytic/ Normochromic Anemias
    • Sickle Cells
    • Target cells
    • NRBCs
    • Howell- Jolly Bodies
    • Polychromatophilia (increased reticulocyte)
  19. Screening Hgb S
    • Cappillary Stasis
    • Metabisulfate
    • Dithionite (Sodium Hydrosulfate)
  20. Metabisulfate Method
    • Hgb is insoluble in low O2 concentration & perpetuates out.
    • Metabisulfate chemically lowers concentration of O2 in the sample causing sickling of the cells.
  21. Metabisulfate reagents
    • EDTA Whole Blood
    • 2% metabisulfate
  22. Metabisulfate Method
    • Place 1 drop of EDTA whole blood on slide.
    • Add 2 drops 2% metabisulfate to blood and mix.
    • Coverslip and seal with vaseline.
    • Let stand for 30 minutes.
    • Observe for Sickling.
  23. Dithionite Method Principle
    • Hgb S insoluble in low O2 concentration.
    • Dithionite chemically lowers O2 Concentration in test sample causing Hgb to PPT out.
    • Precipitation of Hgb S causes turbidity.
  24. Dithionite Method Reagents
    • EDTA Whole Blood
    • Saponin (Lysing Agent)
    • Dithionite (sodium hydrosulfate) ASA reducing agent.
  25. Dithionite Method Procedure
    • Add Saponin and Dithionite reagent to a test tube.
    • Add blood sample to reagent & mix.
    • Allow sample to sit at room temp for 10-15 minutes.
    • Appearance of turbidity is positive for Hgb S & C.
  26. Hemoglobin Electrophoresis
    • Movement of charged particles in an electric field.
    • Negative charged particles migrate toward positive pole (anode)
    • Alkaline Ph gives proteins a negative charge.
  27. Types of Hgb Electrophoresis
    • Cellulose Acetate @ Alkaline Ph.
    • Citrate Agar @ Acid Ph
  28. Electrophoresis Cellulose Acetate Order
    • Hgb A1 closest to anode.
    • F/G next
    • S/D next
    • A2
    • Hgb C/E closest to cathode.
  29. Electrophoresis Citrate Agar Order
    • Hgb F closest to anode
    • Then A1,G,D,E
    • S next
    • Hgb C closest to cathode & behind application point.
  30. Thalassemias
    • Due to Abnormal synthesis of Hgb chains.
    • Most common inherited disorder worldwide.
  31. What type of cells doThalassemias produce?
    • Produce Microcytic Hypochromic Anemia with poikilocytosis.
    • Schistocytes, NRBCs, target cells, basophilic stipling.
  32. Types of Thalassemia
    • Alpha Thalassemia- production of alpha chains is affected.
    • Beta Thalassemia-Production of beta chains is affected.
  33. Alpha Thalasemia
    • Production of Alpha chains is abnormal.
    • All hemoglobins affected.
  34. Distribution of Alpha Thalassemia.
    • Middle East, Orient, SE Asia
    • 25% of Thailand have Alpha Thalassemia.
    • 30% of African Americans are silent carriers.
  35. Distribution of Beta Thalassemia.
    • Production of beta chains is abnormal.
    • Seen in Mediterranean Populations.
    • Jewish, Greek, Italians.
    • 5-10% of population are heterozygous.
  36. Autosomal Dominant Minor.
    • Heterozygous State
    • Alpha Thalassemia Minor
    • Beta Thalassemia Minor
  37. Autosomal Dominant Major
    • Alpha Thalassemia Major
    • Beta Thalassemia Major.
  38. Beta Thalassemia Inheritance
    • 2 Genes for productions of beta chainson CH#11
    • Called B0 & B+
    • B0 produces no beta chains.
    • B+ has decreased productions
  39. 4 Patterns of Beta Thalassemia Inheritance
    • Silent Carrier
    • B Thalassemia Minor
    • B Thalassemia Major
    • Thalassemia Intermedia
  40. Beta Silent Carrier
    • Production of Beta chains is nearly normal, slightly decreased.
    • No Hematological Abnormalities noted.
  41. Minor Beta Heterozygous
    • Mild microcytic hypochromic anemia.
    • Target cells, Elliptocytes, & basophillic stippling seen on peripheral smear.
    • Conc of Hgb A2 & Hgb F are increased.
  42. Beta Thalassemia Intermedia
    • Minimum Hgb of 7g/dl w/o transfusion.
    • NRBCs seen on peripheral smear.
    • Concentration of Hgb A2 & Hgb F are increased.
  43. Alpha Thalassemia Inheritance
    • 4 genes for the production of alpha chains on CH#16.
    • Inherit 1 from each parent Alpha 1 & Alpha 2.
  44. Alpha Thalassemia gene defects
    • No production = no functioning gene on CH#16
    • Decreased Production= 1 functioning gene on ch#16
  45. 4 Inheritance of Alpha Thalassemia.
    • Silent Carrier
    • Alpha Thalassemia Minor (Heterozygous)
    • Hgb H disease.
    • Alpha Thalassemia Major (Hydrops Fetalis)
  46. Silent Alpha Carrier
    • Due to deletion of 1 gene with 3 functioning genes.
    • Production of Alpha Chains is affected only slightly.
    • Hematologically normal appearance.
  47. Alpha Thalassemia Minor
    • Heterozygous.
    • Due to only 2 functioning genes.
    • Individual produces 2-10% Burt's Hgb.
    • Bart's Hgb is 4 gamma strains.
    • Hematologically mild microcytic anemia.
  48. Hgb H disease.
    • Only 1 functioning gene.
    • Common in southeast Asia.
  49. Alpha Thalassemia Major
    • Hydrops Fetalis
    • No Functioning genes.
    • Produced 80% bart's Hgb
    • No functioning A
    • Causes death in utero or shortly after birth.
  50. Bart's Hgb Alpha Thalassemia association.
    • 1 gene deleted - 1-3% bart's
    • 2 genes deleted 4-10% bart's
    • 3 genes deleted Hgb H disease 15-25% bart's & 10-25% H
    • 4 genes deleted Fetal Death 100% bart's
Author
moses1424
ID
69710
Card Set
Thalassemia and Sickle Cell Hemoglobinopathy
Description
Thalassemia and Sickle Cell Hemoglibinopathy
Updated

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