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Haematology Lectures > L.7 Haemoglobinopathies > Flashcards

L.7 Haemoglobinopathies Flashcards

1
Q

What mutation is associated with Hb C?

A

β6 Glu>Lys

Hb C is characterized by a mutation that leads to mild haemolytic anaemia.

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2
Q

What percentage of patients with SCD have Hb S/C?

A

Accounts for 20-50%

Hb S/C is associated with less severe vaso-occlusive complications.

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3
Q

What is the mutation in Hb E?

A

β26 Glu>Lys

Hb E is probably the most common Hb variant globally and homozygotes exhibit mild anaemia.

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4
Q

What is the mutation associated with Hb D?

A

β121 Glu>Gln

Hb D is mostly asymptomatic.

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5
Q

True or False: Hb E homozygotes experience severe anaemia.

A

False

Hb E homozygotes typically have mild anaemia.

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6
Q

Fill in the blank: Hb C is characterized by a mutation from Glu to _____ at position 6.

A

Lys

This mutation leads to mild haemolytic anaemia.

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7
Q

Fill in the blank: Hb S/C accounts for _____ percent of patients with SCD.

A

20-50

It is associated with less severe vaso-occlusive complications.

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8
Q

What is the clinical significance of Hb D?

A

Mostly asymptomatic

Hb D does not typically cause health issues.

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9
Q

What is the typical hemoglobin level (Hb) in alpha-thalassaemias?

A

Hb ↓(70-100 g/l)

A decreased hemoglobin level is a key indicator in alpha-thalassaemias.

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10
Q

What are the changes observed in MCV and MCH in alpha-thalassaemias?

A

MCV↓ MCH ↓

Mean Corpuscular Volume (MCV) and Mean Corpuscular Hemoglobin (MCH) are both decreased.

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11
Q

What are the main findings in a blood film for alpha-thalassaemias?

A
  • Hypochromic Microcytes
  • Target Cells
  • Anisopoiklocytosis
  • Polychromasia
  • NRBC
  • Pappenheimer Bodies
  • Basophillic Stippling

These findings indicate various abnormalities in red blood cells.

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12
Q

What is the significance of reticulocytes in the diagnosis of alpha-thalassaemias?

A

Reticulocytes

Elevated reticulocyte counts can indicate increased red blood cell production.

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13
Q

What laboratory results are typically elevated in alpha-thalassaemias?

A
  • LDH ↑
  • Bilirubin ↑

Elevated levels of lactate dehydrogenase (LDH) and bilirubin are often observed.

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14
Q

What happens to haptoglobin levels in alpha-thalassaemias?

A

Haptoglobin ↓

Decreased haptoglobin levels can indicate hemolysis.

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15
Q

What is the appearance of H Prep when incubated with brilliant Cresyl Blue in alpha-thalassaemias?

A

Unstable HbH precipitations seen as Typical golf ball appearance (30-90%)

This appearance is a characteristic finding in the H Prep test.

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16
Q

What peaks are identified in HPLC for alpha-thalassaemias?

A
  • Hb H peak
  • Hb Barts peak

These peaks indicate the presence of specific hemoglobin types associated with the disorder.

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17
Q

What role do family studies play in the diagnosis of alpha-thalassaemias?

A

Family studies

They help in understanding the inheritance patterns and potential genetic links.

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18
Q

What is the purpose of DNA analysis in diagnosing alpha-thalassaemias?

A

To confirm genetic mutation

DNA analysis provides definitive confirmation of the genetic basis of the disorder.

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19
Q

What is the hemoglobin level in β-Thalassemia Minor?

A

Slightly low (10–13 g/dL)

This indicates a mild reduction in hemoglobin levels.

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20
Q

What is the hemoglobin level in β-Thalassemia Major?

A

Very low (≤7 g/dL)

This reflects severe anemia in β-thalassemia major.

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21
Q

What is the MCV level in β-Thalassemia Minor?

A

Low (<80 fL, microcytic)

Indicates smaller than normal red blood cells.

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22
Q

What is the MCV level in β-Thalassemia Major?

A

Very low (<70 fL)

Signifies a more severe microcytic condition.

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23
Q

What is the RBC count in β-Thalassemia Minor?

A

Normal or high

This may vary but typically remains stable.

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24
Q

What is the RBC count in β-Thalassemia Major?

A

Markedly increased

Reflects the body’s attempt to compensate for severe anemia.

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25
What findings are seen in the Peripheral Blood Smear of β-Thalassemia?
* Microcytosis and hypochromia * Target cells (codocytes) * Basophilic stippling * Nucleated RBCs (normoblasts) * Anisocytosis & poikilocytosis ## Footnote These findings help identify the severity and type of thalassemia.
26
What is the reticulocyte count in β-Thalassemia Minor?
Slightly increased ## Footnote Indicates a mild increase due to the body's response to low hemoglobin.
27
What is the reticulocyte count in β-Thalassemia Major?
Increased due to hemolysis ## Footnote Reflects the body's attempt to produce more red blood cells in response to anemia.
28
What is the gold standard test to identify abnormal hemoglobin levels?
Hemoglobin Electrophoresis (or HPLC) ## Footnote This test is crucial for diagnosing various hemoglobinopathies.
29
What is the level of HbA in β-Thalassemia Minor?
Reduced (80–90%) ## Footnote This indicates a decrease in normal hemoglobin due to thalassemia.
30
What is the level of HbA in β-Thalassemia Major?
Absent or very low ## Footnote This is a key feature distinguishing major from minor.
31
What is the level of HbA2 in β-Thalassemia Minor?
Increased (>3.5–7%) ## Footnote Helps differentiate β-thalassemia minor from iron deficiency anemia.
32
What is the level of HbF in β-Thalassemia Minor?
Normal/slightly high ## Footnote Indicates fetal hemoglobin levels remain stable.
33
What is the level of HbF in β-Thalassemia Major?
Very high (>90%) ## Footnote Reflects the body's compensation by producing fetal hemoglobin.
34
What are the serum iron levels in β-Thalassemia?
Normal or high ## Footnote This differentiates it from iron deficiency anemia.
35
What are the serum iron levels in Iron Deficiency Anemia?
Low ## Footnote This is a key indicator of iron deficiency.
36
What is the ferritin level in β-Thalassemia?
Normal or high ## Footnote Suggests adequate iron stores.
37
What is the ferritin level in Iron Deficiency Anemia?
Low ## Footnote Indicates depleted iron stores.
38
What is the Total Iron Binding Capacity (TIBC) in β-Thalassemia?
Normal or low ## Footnote This indicates that iron binding capacity is not elevated.
39
What is the Total Iron Binding Capacity (TIBC) in Iron Deficiency Anemia?
High ## Footnote Reflects the body's attempt to increase iron uptake.
40
What is the role of molecular/genetic testing in β-Thalassemia?
Confirms β-thalassemia mutations in the HBB gene ## Footnote Useful for carrier screening, prenatal diagnosis, and in severe cases.
41
What is the typical Hb level in Sickle Cell Anaemia?
Hb ↓(30-100 g/l)
42
What are the key findings in a blood film for Sickle Cell Anaemia?
* Hypochromic Microcytes * Target Cells * Sickle Cells * Polychromasia * NRBC * HJ bodies if hyposplenic
43
What laboratory tests show increased levels in Sickle Cell Anaemia?
* LDH ↑ * Bilirubin ↑
44
What is the significance of the Solubility Test in Sickle Cell Anaemia?
Positive result indicates the presence of Hb S
45
What are the HPLC findings in Sickle Cell Anaemia?
* Hb A absent * Hb S 80-100% * Hb F 5-15% * Increased HbA2
46
What genetic analysis can confirm Sickle Cell Anaemia?
DNA analysis to confirm genetic mutation
47
What are the types of thalassaemia based on globin chain synthesis?
* α 0 or β 0 thalassaemias (complete absence) * α + or β + thalassaemias (reduced rate)
48
What are the clinical divisions of thalassaemia?
* Thalassaemia major: Severe anaemia, transfusion dependent * Thalassaemia intermedia: Severe to mild hypochromic microcytic anaemia * Thalassaemia minor: Clinically asymptomatic carrier state
49
What is the pathophysiology of beta-thalassaemia related to globin chain synthesis?
Reduced or absent beta-globin production leads to excess alpha-globin chains
50
What occurs due to alpha-globin precipitation in beta-thalassaemia?
Oxidative stress, membrane damage, and premature apoptosis of erythroid precursors
51
What are the consequences of ineffective erythropoiesis in beta-thalassaemia?
* Bone marrow expansion * Skeletal deformities * Extramedullary hematopoiesis leading to hepatosplenomegaly
52
What causes iron overload in beta-thalassaemia?
* Increased intestinal iron absorption * Repeated blood transfusions
53
What are the normal alpha-globin gene structures?
HBA1 and HBA2 genes on chromosome 16 encode alpha-globin chains
54
What is the effect of one gene deletion in alpha-thalassemia?
Silent Carrier: No symptoms, normal hemoglobin
55
What characterizes Hemoglobin H (HbH) Disease?
Moderate-severe hemolytic anemia, splenomegaly, jaundice
56
What is the genotype for Hemoglobin Bart’s Hydrops Fetalis?
−−/−− (Four alpha chain (HBA1+HBA2) gene deletions)
57
What happens in alpha-thalassemia regarding globin chain production?
Deficiency of alpha-globin chains leads to excess beta and gamma globin chains
58
What is the significance of Heinz Bodies?
Indicate precipitated unstable hemoglobin, seen in Hemoglobin H disease
59
What causes Basophilic Stippling?
Aggregation of ribosomal RNA due to defective hemoglobin synthesis
60
What do Pappenheimer Bodies indicate?
Iron overload due to defective hemoglobin production
61
What is the appearance of Target Cells (Codocytes)?
RBCs with a bull’s-eye appearance
62
What do Howell-Jolly Bodies signify?
Nuclear remnants in RBCs due to ineffective erythropoiesis or splenectomy
63
What is the main treatment for severe forms of thalassemia?
Regular red blood cell transfusions
64
What is the goal of blood transfusions in thalassemia treatment?
Maintain hemoglobin (Hb) levels around 9–10 g/dL
65
What are the types of iron chelation therapy?
Iron overload therapy * Deferoxamine (Desferal) * Deferasirox (Exjade, Jadenu) * Deferiprone (Ferriprox)
66
What is the only curative option for β-thalassemia major?
Hematopoietic Stem Cell Transplantation
67
What is an emerging treatment option for β-thalassemia?
Gene Therapy (Lentiviral-based gene therapy)
68
Fill in the blank: Regular monitoring of serum ferritin and MRI scans is essential for _______.
iron overload assessment
69
True or False: Splenectomy is considered for cases with massive splenomegaly or hypersplenism.
True
70
HbH genetic mutation
3 alpha gene are deleted or mutated, leaving only one functional gene. Excess beta globin chains form unstable tetramers = HbH HbH has reduced oxygen carrying capacity and tend to precipitate damaging RBCs.
71
Hb Barts genetic mutation
No alpha or beta globin chains. Cannot form HbA or HbF. To compensate cells make 4 y globin chains = HbBarts. Extremely high affinity for oxygen so do not release oxygen efficiently to tissues
72
Why is haptoglobin raised in a-thalassaemia?
1. Increased RBC intravascular + extravascular haemolysis due to unstable Hb variants which precipitate and damage RBC membranes. 2. Haptoglobin (plasma protein) binds free Hb released from lysed RBCs. 3. haptoglobin-haemoglobin complex is cleared rapidly by the liver leading to low Haptoglobin levels.
73

Haematology Lectures (16 decks)

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