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Flashcards in Hemoglobinopathies Deck (60)
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1

defective globin switching

persistence of fetal hemoglobin

2

microcytosis

small cells

3

hydrops fetalis

fetal death due to complete lack of alpha hemoglobin genes

4

What is the embryonic hemoglobin?

HbG

4

The tense hemoglobin state is the ______ state, while the relaxed state is _______ and planar.

deoxygenated; oxygen-bound

5

Where are most structural hemoglobin variants found?

in the Beta-globin chain

5

hemoglobin H disease

severe anemia because only 1/4 alpha globin gene is functional

6

What is non-covalently linked in between the globins?

iron and a heme group

6

How many genetic variants of hemoglobin are known?

600

7

What is the fetal hemoglobin?

HbF (alpha 2 gamma 2)

8

How do you test for sickle cell?

1) DNA sequencing with PCR or electrophoresis 2) southern blot

8

Thalassemia minor

mild phenotype; doesn't req transfusions

9

In beta-thalassemia, defects are seen _____.

postnatally only

10

How are hemoglobin C and hemoglobin S different?

Same codon, different mutations, different phenotypes

11

HbKemsey has _____ O2 binding while hemoglobin Kansas has ______ O2 binding.

too tight; too weak

12

Which form of hemoglobin is the best oxygen carrier?

alpha-beta

13

Where is hemoglobin synthesized?

in the bone marrow

14

How many copies of the beta globin gene are there?

1

14

What is the major adult hemoglobin?

HbA

14

In HbKempsey, the O2 binding affinity is _____, so _____ O2 is delivered to the tissues, and to compensate, red blood cells are ________. This condition is called _______.

higher; less; overproduced; polycythemia

16

The 5'-3' ____ order of genes within each cluster coincides with the _____ order of their expression during development.

spatial; temporal

17

structural variants/qualitative hemoglobinopathies

mutations that alter the globin's properties without affecting its synthesis

18

Phenotypically, having 2 out of the 4 alpha globin genes results in _____.

mild anemia

19

How many oxygens does each globin bind?

one each; 4 per molecule

19

hypochromia

pale blood cells

20

What is hereditary persistence of fetal hemoglobin?

benign conditions that impair the perinatal switch from gamma to beta globin synthesis (high GbF in adults)

21

Beta-thalassemia is most often caused by _______.

point mutations in the beta-globin gene

22

Alpha-thalassemia is a ______ of alpha-globin and an excess of _____.

low or no amount; beta and gamma

23

thalassemia major

beta-zero; no beta proteins being produced

24

How many identical copies of the alpha globin gene are there on each chromosome?

2