thalassemia syndromes Flashcards

1
Q

Describe 3 mechanisms for hemoglobinopathies.

A
  1. abnormal hemoglobin
  2. reduced rate of production of Hb chains
  3. persistence of fetal hemoglobin
    Most are Genetic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe normal hemoglobin structure.

A

HbA: a2b2
HbA2: a2d2
HbF: a2y2be

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the genotypes of beta-thalassaemia major, intermedia, and minor?

A

minor: B+/B or B0/B, one normal allele
intermedia: Very rarely can have one but usually have two mutant alleles, often with other modifying factors
Major: Two mutant alleles, e.g., B+/B+, B+/B0, B0/B0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the features of beta thalassemia minor?

A

microcytic, increased number of cells, target cells, Hb a little low, no clinical problems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the features of beta thalassemia major?

A

Homozygous, more severe form of disease.

  • lack of beta glob in chain production
  • anemia from 3 months onward, born normally (have Hb F)
  • bloated abdomen
  • crew cut appearance of skull
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the genotypes of alpha thalassemia?

A
  • 1 gene deletion: mild microcytosis, occasional Hb H bodies inside cells. Little clinically
  • 2 gene deletion: cis or trans-mild anemia, lightly increase RBC, cis worst because can pass on
  • 3 genes deletion: HbH disease. Severe anemia
  • 4 gene deletion: still born, Hydrops Fetalis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the pathogenesis of thalassemia?

A

unbalanced chain synthesis
Precipitate on nuclear membrane –>apoptosis (ineffective erythropoiesis)
precipitate on cell membrane → destruction by macrophage in spleen/liver (hemolysis)
-Dyserythropoiesis and reduced red cell survival < 10 minutes–>hypersplenism
-overactive marrow–>bone changes, facial changes, increased fractures, increased plasma volume, effective protein malnutrition/stunting, increased GIT iron absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the treatment for thalassemia major?

A

transfusion and chelation therapy.

  • vaccinations
  • splenectomy when needed
  • vaccination against encapsulated baceria: meningococcal and pneumococcal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe Hb E.

A
  • common in South East Asia
  • beta globin mutation glu–>lys
  • ->chain imbalance, more alpha chains
  • heterozygotes: like thalassemia minor
  • homozygotes: severe microcytosis, little anemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly