Hemoglobinopathy cards Flashcards

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1
Q

What is the primary function of RBCs

A

To synthesize hemoglobin

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2
Q

How many hemoglobin molecules does each RBC have?

A

640 million

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3
Q

How many RBCs does a human have?

A

20-30 trillion

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4
Q

What is the primary function of gemoglobin?

A

Transport oxygen to the tissues

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5
Q

Hemoglobin is tetrameric, what does this mean?

A

it is composed of 4 subunits

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6
Q

Heme is a _ group

A

prosthetic

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7
Q

Globin is a _ of protein

A

chain of protein

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8
Q

What is heme derived from?

A

porhyrin

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9
Q

What element do hemes contain?

A

Fe 2+

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10
Q

Two subunits of globin are _-like and the other two are _-like

A

Alpha like and beta like

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11
Q

What is erythropoiesis?

A

Prodution of RBCs

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12
Q

What glycoiprotein regulates erythropoiesis?

A

EPO - Erythropoietin

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13
Q

What happens when renal cells detect decreased oxygen in circulation available for metabolism.

A

The kidney’s renal cells secrete EPO which is the glycoprotein that regulates the production of RBCs (erythropoiesis)

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14
Q

What does not having enough RBCs result in?

A

Anemia

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15
Q

What does having too many RBCs result in?

A

Higher risk for cardiovascular events like strokes, myocardial infarctions etc

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16
Q

Successful erythropoiesis depends on what three things?

A
  1. Stimulus to produce erythrocytes. 2. Response to the stimulus with adequate productionj of precursors. 3.Adequate nutrients for synthesis of erythrocytes.
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17
Q

How long to healthy people recirculate RBCs for?

A

3-4 months

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18
Q

A hematopoietic stem cell in the presence of EPO will give rise to what?

A

Erythroblast

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19
Q

What must be inserted into the heme of an erythroblast?

A

Iron

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20
Q

Erythroblast + iron =

A

Reticulocyte

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21
Q

What is the precursor RBC?

A

Reticulocytes, named for its morphology

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22
Q

What happens if globins and heme groups arent produced in stoichiometric ratios?

A

RBCs can malfunction. MUST be produced in stoichiometric ratios.

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23
Q

Where are globins synthesized?

A

In ribosomes

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24
Q

Where are hemes synthesized?

A

in mitochondria

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25
Q

A healthy globin requires 2 _ and 2 _

A

2 alpha-like and 2 beta-like chains

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26
Q

What are the alpha like chains?

A

Alpha and zeta

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27
Q

What are the beta like chains?

A

beta, epsilon, delta, gamma

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28
Q

What is more detrimental, a decrease in alpha-like chains of beta-like chains?

A

Alpha-like chains

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29
Q

What genes are on chromosome 16?

A

Alpha 1 and Alpha 2 genes

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30
Q

What genes are on chromosome 11?

A

Delta and beta

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31
Q

What is A-thalassemia major?

A

Missing all 4 copies of alpha 1 and alpha 2 gene

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32
Q

What is A-thalassemia minor?

A

3 Functioning copies of the gene?

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33
Q

What is Hb Lepore?

A

Misalignment due to the similarity of the sequences of the alpha and beta genes

34
Q

What does Lepore manifest as? What is the inheritance pattern?

A

B-thalassemia, Autosomal recessive

35
Q

What symptoms present in anti lepore?

A

None, asymptomatic

36
Q

What is hematocrit?

A

Ration of RBCs to plasma expressed as total % of blood volume

37
Q

WHO definition for anemia in men and women?

A

Less than 13 g/dL for men and less than 12 g/dL women

38
Q

2 examples of acute anemia?

A

Blood loss and preganancy due to sharing blood volume with fetus

39
Q

3 examples of chronic anemia?

A

Hemolytic (G6PD), Sickle Cell, Impaired production of RBCs

40
Q

3 examples of impaired production of RBCs?

A

Nutritional deficiencies, Thalassemia, leukemia

41
Q

What stem cell do erythrocytes come from?

A

Common myeloid progenitor

42
Q

What 3 nutritional deficiencies can cause anemia?

A

Lack of Vitamin B12, folate and iron

43
Q

What 2 genetic abnormalities can cause anemia?

A

Cngenital abnormalities and congenital membranopathies

44
Q

What are the 2 basis’ you can use to classify anemia?

A

Basis of cause and basis of morphology

45
Q

What are the three basis of cause for anemia?

A

Blood loss, inadequate production of normal blood cells and, excessive destruction of blood cells.

46
Q

What causes Macrocytic anemia?

A

Stuck in G2 phase instea of progressing to M phase due to lack of cobalamin (b9) and folate deficiency

47
Q

What cases microcytic anemia?

A

Heme deficiency activates a feedback mechanism to inihibit globin and protein synthesis.

48
Q

What is the most common family of diseases with mendelian inheritance?

A

Hemoglobinopathies

49
Q

Mutation of what gene causes sickle cell anemia?

A

Beta globin gene, 6th AA is changed from Glu to Val

50
Q

What is sickling?

A

HbS polymerizes when deoxygenated to form a network of fibrous polymers that stiffen the RBC membrane

51
Q

What is SSA inheritance pattern?

A

Autosomal recessive

52
Q

What can SSA cause for a patient?

A

The sickle cell shape may cause microvascular occlusion because RBC are sticky and haemolytic anemia

53
Q

2 ways to screen for SSA?

A

Heel prick and solubility test

54
Q

How are SSA heterozygotes affected by malaria?

A

Resistant to malaria without severe anemia

55
Q

What is sickle cell disease?

A

Homozygote with reduced life expectantcy

56
Q

What is sickle cell trait?

A

Heterzoygote with normal life expectancy but risks crisis when exercising at high altitude

57
Q

What is a thalassemia?

A

A decreased production of one or more of the globin chains

58
Q

What does excess accumulation cause?

A

leads to the accumulation and precipitation and precipitation causes hemolysis and hyper placia of red bone marrow

59
Q

What is A-thalassemia?

A

Reduced or absent synthesis of alpha globin chains.

60
Q

What is B-thalassemia?

A

Reduced or absent synthesis of Beta globin chains.

61
Q

_-thalassemia silent:

A

production of 3 of the 4 globin chains no clinical symptoms

62
Q

_-thalassemia trait:

A

2 _ globins are present: microcytic hypochromic anemia, often mistaken for iron deficiency may cause mild anemia symptoms if there is a sufficient production of _-globin

63
Q

Hemoglobin H disease:

A

there are mutations on 3 globin genes

64
Q

HbH:

A

beta globin tetramers take oxygen, precpitate and lyse the cell and, cause hypochromic microcytic anemia with

65
Q

Hb Barts tetramer type?

A

Gamma tetramer

66
Q

Hydropic Fetus (hydrops fetalis):

A

Mutation on 4 globin genes, fatal due to no alpha chains are made

67
Q

B-Thalassemia Minor:

A

heterozygous = 1 functional copy of B-globin

68
Q

B-Thalassemia Minor symptoms and treatment?

A

No symptoms or very mild anemia. No treatment necessary

69
Q

B-Thalassemia Major:

A

homozygous recessive = Not immediately lethal because you can increase expression of epsilon (Hb F), delta and gamma globins

70
Q

B-Thalassemia Major treatment and symptoms?

A

Symptoms appear by 2 years old with severe anemia. Transfusions necessary with death in teens or early adulthood.

71
Q

Beta-delta Thalassemia:

A

Under production of both beta and delta chains

72
Q

What is G6PD inheritance pattern?

A

x-linked recessive

73
Q

What does G6PD deficiency inhibit and cause in RBCs?

A

Inhibits the ability of PPP to make NADPH which is fundamental for reactive oxygen species detoxification causes lysis in RBCs- short life span

74
Q

What is hereditary spherocytosis? What membrane proteins are affected?

A

Mutations on genes that regulate RBC shape changing it to spherical instead of biconcave. Spectrin or ankirin

75
Q

Why are spherical RBCs bad?

A

Interfere with cell;s ability to squeeze into small capilaries

76
Q

What is hereditary spherocytosis’ inherticance pattern?

A

can be autosomal domminand or autosomal recessive

77
Q

What is porphyria?

A

Porphyrins and their precursors accumulate in different organs/tissues.

78
Q

What mutations cause porphyria?

A

Mutations on genes coding for enzymes necessary for heme synthesis

79
Q

What porphyria causes abdominal and neurologic symptoms?

A

Hepatic porphyria

80
Q

What porphyria causes cutaneous symptoms and photosensitivity??

A

Erythropoietic porphyria

81
Q

What are the S/S of mixed porphyria?

A

S/S of borth hepatic and erythropoietic