Hemoglobin disorders final

Hemoglobin disorders Biochemistry Report

1. Hemoglobin Diseases GROUP 10 Reporters: Yang, Sheryl Ray Zagada , Timothy Zamora, Marvin Zapanta , Patricia Joyce

2. Hemoglobin 101 Yang, Sheryl Ray

3. Primary function of the Red blood cell is to manufacture hemoglobin, which in turn, transports oxygen to the tissues and carbon dioxide from tissues to the lungs. Hemoglobin molecule is composed of four subunits, each containing heme and globin Hemoglobin Synthesis 1 Heme = 1 mol of O2 1 Hemoglobin = 4 mol of O2

4. Protein component called globin Four molecules of the nitrogenous substance Protoporhpyrin IX Four Iron atoms at Ferrous (Fe +2 ) state that combine with Protoporphyrin IX to form four heme molecules One 2,3 Diphosphoglycerate (2,3 DPG) molecule as a sometime resident in the center of Hb unit Hemoglobin Synthesis Components of Hemoglobin

5. Heme Synthesis

6. Heme Synthesis

7. Produced on specific ribosomes in the cytoplasm of red blood cells. The globin in each hemoglobin molecule consists of four polypeptide chains which determine the type of hemoglobin formed. Globin Chains

8. Greek Designation Greek Name No. of Amino Acids Chromosome α Alpha 141 16 β Beta 146 11 δ Delta 146 11 γ Gamma 146 11 ε Epsilon 146 11 ζ Zeta 146 16 Globin Chains in Hemoglobin Consist of varied sequences of amino acids – polypeptide chains

9. Hemoglobin Molecular structure Stage of life Proportion Newborns Proportion Adults Portland 2 Zeta + 2 Gamma Embryonic Gower I 2 Zeta + 2 Epsilon Embryonic Gower II 2 Alpha + 2 Epsilon Embryonic Hb A1 2 Alpha + 2 Beta Newborn & Adult 20 97 Hb A2 2 Alpha + 2 Delta Newborn & Adult <0.5 2.5 Hb F (Fetal) 2 Alpha + 2 Gamma Newborn & Adult 80 <1 Normal Human Hemoglobin

10. Hemoglobin Molecule Hb A1

11. T and R states of Hemoglobin • Hemoglobin exists in two major conformational states: Relaxed (R ) and Tense (T) • R state has a higher affinity for O2. • In the absence of O2, T state is more stable; when O2 binds, R state is more stable, so hemoglobin undergoes a conformational change to the R state. • The structural change involves readjustment of interactions between subunits. Tensed and Relaxed State

12. Tensed and Relaxed State

13. O2- Dissociation Curve

14. Iron in the ferrous state is required to convert protoporphyrin Ix to heme . Circumstances that cause reduction in the iron available for Hb synthesis or failure to incorporate iron into heme will cause anemia to develop. Iron Metabolism for Heme Synthesis

15. Most common cause of anemia Due to INCREASED PHYSIOLOGIC DEMANDS Rapid growth; infants, children Pregnancy, lactation Iron Deficiency Anemia * INADEQUATE INTAKE * Iron deficient diet * Inadequate absorption * CHRONIC BLOOD LOSS * Menstrual flow * Gastrointestinal bleeding * Regular blood donation * Chronic hemolysis

16. Effect of IDA Protoporhyrin IX Fe +2 Ferroprotoporphyrin IX (HEME) Hemoglobin

17. Hemoglobinopathy Conditions caused by qualitative structural abnormalities of the globin polypeptide chains that result from alteration of the DNA genetic code for those chains Hemoglobinopathies and Thalassemias

18. Thalassemias Conditions caused by quantitative abnormality in globin chain (i.e., reduced or no production). Hemoglobinopathies and Thalassemias

19. Sickle Cell Anemia Zamora, Marvin

20. Hgb S – most common abnormal hemoglobin Normal glutamic acid at 6 th position in the β chain is replaced by Valine Results in: Altered solubility Altered ability to withstand oxidation Instability Increased propensity for methemoglobin production Increased or decreased oxygen affinity Sickle cell disease

21. Sickle cell anemia Sickle cell disease (SCD) Drepanocytosis Hb SS SS disease Hemoglobin S Homozygous

22. Sickle cell trait Is the heterozygous state of SCD One sickle gene and one normal hemoglobin gene (Hb AS) Usually have no symptoms

23. Overview Sickle cell disease is a general term for a group of genetic disorders caused by sickle hemoglobin ( Hgb S or Hb S) Erythrocytes becomes elongated and sickle shaped Removed from the circulation and destroyed at increasing rates, leading to anemia.

24. Overview An autosomal recessive inherited defect The disease is chronic and lifelong Lifespan average of 40 years.

25. Pathophysiology caused by a point mutation in the β-globin chain of hemoglobin glutamic acid valine at the 6th position *found on the short arm of chromosome 11.

26. Pathophysiology Sickling occurs when oxygen decreases at the tissue level – dissociation of oxygen from RBC Polymerization of Hgb molecules to crystals

27. Sickle cell crises Vasoocclusive crises - Increase in blood viscosity - restricts blood flow to an organ Hemolytic crises – acute accelerated drops in Hgb levels and RBCs break down at a faster rate. - common in patients with G6PD deficiency

28. Sickle cell crises Infectious crises - Abnormal splenic function - Depressed immune function - Streptococcus Pneumoniae is the major infectious agent among children

29. Sickle cell crises Aplastic crises - caused by infection and fever - Parvovirus B19 - Folate deficiency

30. Sickle cell crises Bone, joint and other crises: - Hand-foot syndrome or Dactylitis - Priapism - Gallstones

31. Sickle cell anemia Laboratory findings -severe anemia (Hgb 5-9 g/dl) -normocytic, normochromic RBC -aniso and poikilocytosis is present -with leukocytosis and thrombocytosis

32. Diagnosis Blood film appearance Screening tests for sickling Hemoglobin electrophoresis

33. Hemoglobin electrophoresis A (%) F (%) S (%) C (%) D (%) E (%) Degree of clinical abnormality Hemoglobinopathy Hb CC 1-7 >90 Mild Hb AC 50-60 <2 40-50 None Hb SC 1-7 50 50 Mod - Severe Hb SS 1-10 80-90 Severe Hb AS 55-70 <2 30-45 None/Mild Hb DD <2 95 None Hb AD 50-65 <2 35-50 None Hb EE 1-5 95 Mild Hb AE 60-80 20-40 None

34. Treatment *Blood transfusion of PRBC *Administration of antisickling agents -Cyanate -Urea -Nitrogen mustard -zinc procaine hydrochloride, Citiedil, and piracetam *Bone marrow transplantation

35. Thalassemia Zapanta , Patricia Joyce

36. THALASSEMIA SYNDROMES Each individual has 4 genes of hemoglobin ( HBA1, HBA2, HBB1,HBB2 ) ( aa / aa )(bb/bb) Thalassemia is characterized by partial or total absence of one or more chains of hemoglobin (either α chain or β chain). Resulting to abnormal form of hemoglobin. Which leads to destruction of RBC leads to anemia It is a genetic disorder TYPES OF THALASSEMIA 1. α - thalassemia 2. β - thalassemia

37. THALASSEMIA DEMOGRAPHIC Southeast Asia and Meditteranian region CLINICAL PRESENTATION MINOR – mild anemia confused with iron deffeciancy INTERMEDIATE -moderate anemia MAJOR - severe anemia – hydrops fetalis intrauterine death

38. Alpha thalassemia

39. ALPHA THALASSEMIA Involves the genes HBA1 and HBA2 Located at chromosome 16 Severity of disease depends on the number of genes defective or missing

40. Alpha (+) thalassemia: -deletion of I or more alpha globin gene If 1 gene = silent carrier If 2 genes = alpha trait (thalassemia minor) If 3 genes = H hemoglobin (thalassemia intermedia) Alpha (0) thalassemia If 4 genes = Bart hemoglobin (thalassemia major) ALPHA THALASSEMIA

41. 3 normal gene (-a/aa) Normal patient Silent Carrier/ Alpha thalassemia minima/ alpha thalassemia – 2 trait

42. 2 normal gene ( aa /--) – cis form (-a/-a) – trans form Clinically normal Minimal anemia Decrease MCV and MCH Alpha thalassemia trait/ alpha thalassemia minor/ alpha thalassemia – 1 trait

43. Only 1 normal alpha-globin gene (-a/--) Increase ratio beta globin : alpha globin Sensitive to oxidative stress RBC prone to hemolyze Hemoglobin H / HbH disease

44. All 4 alpha globin gene is deleted (--/--) Most severe case Hydrops fetalis Bart ’ s Hemoglobin/ alpha (0) thalassemia

45. BETA THALASSEMIA Β thalassemia will not manifest at birth since predominant is Hgb F. production of B chain will occur only at 3 – 6 months after birth Involves the gene HBB1 and HBB2 Located at chromosome 11 Severe transfusion dependent anemia

46. BETA THALASSEMIA TYPE OF BETA THALASEMIA Homozygous beta thalassemia ( thalassemia major, cooley ’ s anemia, Meditteranean anemia) - severe life long - all beta gene mutated -severe anemia Heterozygous beta thalassemia (thalassemia minor) -one normal beta chain and 1 abnormal beta chain -mild anemia

47. THALASSEMIA LAB DIAGNOSTICS Peripheral Blood Smear -Target cells, Heinze bodies, basophilic strippling, nucleated RBC Reticulocyte – increased Decreased osmotic fragility Iron storage disease

48. As blood glucose enters the erythrocytes it glycosylates the ε -amino group of lysine residues and the amino terminals of hemoglobin. RBC life span – 120 days HbA1c and Diabetes

49. HbA1c and Diabetes

50. HbA1c Normal / abnormal Blood glucose level via meter 4.0 - 6.0% Normal for those without diabetes 3 – 8mmol/L 6.1 – 7.0% Target range for those with diabetes 4 – 8mmol/L 7.1 – 8.0% High 8 – 11mmol/L 8.1 – 9.0% Too high 11 – 14mmol/L Greater than 9.1% Very high 15mmol/L and above HbA1c and Diabetes

51. HbA1c and Diabetes

52. Laboratory Experiment: Hgb Determination Zagada , Timothy

53. Cyanmethemoglobin method A method used for hemoglobin determination The reagent hemolyzes the erythrocytes which releases the hemoglobin into the solution. REACTIVE INGREDIENTS: -potassium cyanide and potassium ferricyanide .

54. Principle in Cyanmethemoglobin method When blood is mixed with a solution containing potassium ferricyanide and potassium cyanide, the potassium ferricyanide oxidizes iron to form methemoglobin . The potassium cyanide then combines with methemoglobin to form cyanmethemoglobin Hgb (Fe ++ ) K 3 Fe(CN) 6 Methemoglobin (Fe +++ ) KCN Cyanmethemoglobin

55. Procedure Hgb Reagent (5ml) Mix well. Stand for 3 min Read at spectrophotometer +20ul blood sample (EDTA whole blood)

56. PURPOSE OF EDTA EDTA ( ethylenediaminetetraacetic acid) is the most commonly used anticoagulant in evacuated tubes. EDTA reduces platelet activation by protecting the platelets during contact with the glass tube that may initiate platelet activation.

57. RESULTS Normal: Male: 13-18 g/ dL Female: 12-16 g/ dL

58. SOURCES OF ERRORS Technical Error Pipeting Use of dirty, scratched or unmatched cuvettes Use of d eteriorated reagents Incorrectly calibrated spectrophotometer

59. SOURCES OF ERRORS Physiologic Error Turbidity in the mixture causes falsely elevated values Turbidity maybe caused by: Lipemia Extremely high leukocyte counts Easily precipitated Globulins

60. Factors that affect Hemoglobin Increased Hemoglobin kidney releases too much erythropoietin People living in high altitudes Anabolic steroid Smoking Dehydration Polycythemia vera

61. Factors that affect Hemoglobin Decreased Hemoglobin - Vitamin-deficiency Anemia deficiency of vitamin B12 or folate - Bleeding Blood volume is replaced more quickly than red blood cells, leading to a lower concentration of hemoglobin - Kidney Disease results in lower levels of erythropoietin -Pregnancy - Blood Disorders