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MD311 Hematology > IL-7 Hemoglobinopathies And Thalassemia > Flashcards

IL-7 Hemoglobinopathies And Thalassemia Flashcards

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1
Q

What is the genetic cause of most cases of alpha-thalassemia?

A

Gene deletions in the alpha-globin genes on chromosome 16

Each person has 4 alpha-globin genes (2 on each chromosome).

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2
Q

How does the severity of alpha-thalassemia depend on the genetic condition?

A

It depends on how many alpha-globin genes are deleted or non-functional.

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3
Q

What are the clinical features of a silent carrier of alpha-thalassemia?

A

No symptoms, normal Hb

Genotype: 3/4 functional.

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4
Q

What are the clinical features of alpha-thalassemia trait (minor)?

A

Mild anemia, microcytosis, normal Hb electrophoresis

Genotype: -a/-a or -/aa, 2/4 functional.

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5
Q

What are the features of Hemoglobin H Disease (HbH)?

A

Moderate-severe anemia, HbH & Bart’s, oxidative hemolysis

Genotype: -I-a, 1/4 functional.

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6
Q

What is the clinical outcome of Hb Bart’s Hydrops Fetalis?

A

Incompatible with life, severe anemia, hydrops fetalis

Genotype: 0/4 functional.

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7
Q

What is the main characteristic of HbH Disease?

A

Only 1 working alpha-gene

Caused by unpaired gamma chains or excess beta chains forming HbH.

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8
Q

What is the significance of Hb Bart’s in terms of oxygen delivery?

A

Hb Bart’s has very high oxygen affinity, so cannot deliver oxygen to tissues.

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9
Q

What are the clinical signs of Hb Bart’s Hydrops Fetalis?

A

Hydrops fetalis, generalized edema, ascites, hepatosplenomegaly, cardiomegaly

Severe hypochromic, microcytic anemia, many NRBCs on blood smear.

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10
Q

True or False: Alpha-thalassemia affects hemoglobin formation only after birth.

A

False

Alpha-globin is required in all stages of hemoglobin synthesis.

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11
Q

What is the impact of excess unpaired beta or gamma chains in alpha-thalassemia?

A

They form abnormal tetramers (HbH or Hb Bart’s) which are less damaging than excess unpaired alpha chains.

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12
Q

List the genotypes associated with alpha-thalassemia trait.

A
  • -a/aa
  • -a/-a
  • -I-a
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13
Q

What is the phenotype-genotype relationship in alpha-thalassemia?

A

Normal, Carrier (asymptomatic), HbH disease (symptomatic), Hemoglobin Bart’s, Hydrops Fetalis.

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14
Q

Fill in the blank: The normal alpha-globin gene is located on chromosome ____.

A

16

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15
Q

What are the features of a normal alpha-thalassemia genotype?

A

Normal

Genotype: 4/4 functional.

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16
Q

What is the Hb typing for Hb H Disease?

A

Hb A 0%, Hb Bart’s 70-80%, Hb H 5-40%.

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17
Q

What are the blood smear characteristics of a neonate with hemoglobin Bart’s hydrop fetalis?

A

Anisocytosis, target cells, numerous nucleated red blood cells (NRBCs).

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18
Q

What is the genetic cause of most cases of alpha-thalassemia?

A

Gene deletions in the alpha-globin genes on chromosome 16

Each person has 4 alpha-globin genes (2 on each chromosome).

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19
Q

How does the severity of alpha-thalassemia depend on the genetic condition?

A

It depends on how many alpha-globin genes are deleted or non-functional.

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20
Q

What are the clinical features of a silent carrier of alpha-thalassemia?

A

No symptoms, normal Hb

Genotype: 3/4 functional.

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21
Q

What are the clinical features of alpha-thalassemia trait (minor)?

A

Mild anemia, microcytosis, normal Hb electrophoresis

Genotype: -a/-a or -/aa, 2/4 functional.

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22
Q

What are the features of Hemoglobin H Disease (HbH)?

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A

Moderate-severe anemia, HbH & Bart’s, oxidative hemolysis

Genotype: -I-a, 1/4 functional.

23
Q

What is the clinical outcome of Hb Bart’s Hydrops Fetalis?

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A

Incompatible with life, severe anemia, hydrops fetalis

Genotype: 0/4 functional.

24
Q

What is the main characteristic of HbH Disease?

Study These Flashcards
A

Only 1 working alpha-gene

Caused by unpaired gamma chains or excess beta chains forming HbH.

25
What is the significance of Hb Bart's in terms of oxygen delivery?
Hb Bart's has very high oxygen affinity, so cannot deliver oxygen to tissues.
26
What are the clinical signs of Hb Bart's Hydrops Fetalis?
Hydrops fetalis, generalized edema, ascites, hepatosplenomegaly, cardiomegaly ## Footnote Severe hypochromic, microcytic anemia, many NRBCs on blood smear.
27
True or False: Alpha-thalassemia affects hemoglobin formation only after birth.
False ## Footnote Alpha-globin is required in all stages of hemoglobin synthesis.
28
What is the impact of excess unpaired beta or gamma chains in alpha-thalassemia?
They form abnormal tetramers (HbH or Hb Bart's) which are less damaging than excess unpaired alpha chains.
29
List the genotypes associated with alpha-thalassemia trait.
* -a/aa * -a/-a * -I-a
30
What is the phenotype-genotype relationship in alpha-thalassemia?
Normal, Carrier (asymptomatic), HbH disease (symptomatic), Hemoglobin Bart's, Hydrops Fetalis.
31
Fill in the blank: The normal alpha-globin gene is located on chromosome ____.
16
32
What are the features of a normal alpha-thalassemia genotype?
Normal ## Footnote Genotype: 4/4 functional.
33
What is the Hb typing for Hb H Disease?
Hb A 0%, Hb Bart's 70-80%, Hb H 5-40%.
34
What are the blood smear characteristics of a neonate with hemoglobin Bart's hydrop fetalis?
Anisocytosis, target cells, numerous nucleated red blood cells (NRBCs).
35
What is B* Thalassemia?
Reduced B-globin production, but not completely absent. ## Footnote Caused by mutations in regulatory regions such as promoter region, 5' UTR, 3' UTR, introns, and coding regions.
36
What characterizes B° Thalassemia?
Complete absence of B-globin production. ## Footnote Results from severe gene defects like initiation codon mutations, splice junction mutations, frameshifts, and nonsense mutations.
37
What is the result of both B* and B° Thalassemia?
Excess a-chains accumulate, leading to ineffective erythropoiesis and hemolysis. ## Footnote This results in anemia due to destruction in marrow and hemolysis in periphery.
38
What defines the Silent Carrier clinical syndrome?
Heterozygous with normal Hb and no symptoms, normal HbA2. ## Footnote It is a mild form of thalassemia.
39
What are the clinical features of B-Thalassemia Minor?
Mild anemia (microcytic, hypochromic), asymptomatic or mild symptoms. ## Footnote Hb level typically ranges from 10-13 g/dL.
40
What is the typical blood smear finding in B-Thalassemia Minor?
Microcytic, hypochromic RBCs with mild anisopoikilocytosis. ## Footnote Presence of target cells, elliptocytes, and occasional basophilic stippling.
41
What is the definition of Thalassemia?
A group of inherited single-gene disorders causing reduced or no synthesis of one or more globin chains, leading to chain imbalance and resulting in ineffective erythropoiesis and hemolytic anemia.
42
What is the management strategy for B-Thalassemia Major?
Regular transfusions starting at ~1 year old and iron chelation therapy. ## Footnote Medications like deferoxamine and deferasirox are used for iron chelation.
43
What are the complications of B-Thalassemia Major?
Transfusional hemosiderosis, cardiomyopathy, liver cirrhosis, endocrine dysfunction, alloimmunization, risk of transfusion-transmitted infections. ## Footnote Infections may include HIV and hepatitis.
44
What are the clinical features of B-Thalassemia Major (Cooley's Anemia)?
Severe anemia, transfusion-dependent, presents at 6-12 months of age. ## Footnote Symptoms include growth retardation, delayed puberty, and craniofacial deformities.
45
What are the blood smear findings in B-Thalassemia Major?
Severe microcytic, hypochromic anemia with extreme poikilocytosis, target cells, teardrop cells, and elliptocytes. ## Footnote Reticulocyte count is inappropriately low due to ineffective erythropoiesis.
46
What is the typical Hb pattern in B-Thalassemia Minor?
Mostly HbF, slight HbA2, little to no HbA.
47
What defines the genotype for B-Thalassemia Major?
Homozygous (or compound heterozygous) B° or * mutations leading to no or very low ß-chain production.
48
What is the MCV range in B-Thalassemia Major?
MCV typically ranges from 50-60 fL.
49
True or False: B-Thalassemia Minor usually requires treatment.
False.
50
Fill in the blank: B-Thalassemia is characterized by ineffective __________ and hemolytic anemia.
erythropoiesis
51
What are the expected Hb levels in B-Thalassemia Major?
Hb levels typically range from 4-8 g/dL.
52
What is the typical reticulocyte count in B-Thalassemia Major?
Retic count is 2-8%, inappropriately low due to ineffective erythropoiesis.
53
What are the common features of blood smear findings across B-Thalassemia types?
Microcytic/hypochromic anemia, polychromasia, anisocytosis, poikilocytosis, and presence of target cells.

MD311 Hematology (16 decks)

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