Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Fundamentals Block 3 > hemoglobinopathies > Flashcards

hemoglobinopathies Flashcards

1
Q

what type of inheritance pattern is sickle cell anemia?

A

autosomal recessive disorder

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

what are sickle cells

A

deoxygenated hemoglobin that forms long polymers
-block vessels causing pain crises and tissue infarction especially the marrow and spleen

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

what causes moderate to severe hemolytic anemia?

A

repeated sickling crises

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

describe normal adult hemoglobin

A

> 95% HbA
<4% HbA2
<1% fetal hemoglobin

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

HbA

A

a2B2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

HbA2

A

a2δ2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

HbF

A

a2Y2

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

in sickle cell disease, B-globin chain has a point mutation at the 6th codon that causes what change?

A

glutamate to valine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

sickle cell disease vs sickle cell trait

A

disease is homozygous-symptomatic
trait is heterozygous, asymptomatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what percent of Africans are heterozygous for HbS?

A

up to 30%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does the sickle cell trait protect from?

A

malaria falciparum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what percentage of African Americans have sickle cell trait?

A

8-10%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what percentage of African Americans have sickle cell disease?

A

0.17%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the complications that arise from vaso-occlusive crisis?

A

-pain crisis
-chronic hypoxia
-infarction (tissue death bc of lack of blood)
-acute chest syndrome-lung infection
-stroke
-sequestration crisis- in spleen of children
-aplastic crisis - parvovirus B19 (body stops making blood cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the clinical course that can cause vaso-occlusive complications?

A

-genetic
-cigarette smoke, respiratory infection, hydration, high altitude

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

at what age does complete splenic autoinfarction occur in sickle cell disease patients?

A

by age 20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what type of infections are SCD patients susceptible to?

A

encapsulated organisms bc the spleen is impaired and can’t remove them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Sickledex test

A

-screening test for sickle cell anemia
-mix blood with matebodulfite (reducing agent)—>sickling
-does not distinguish disease from trait

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

why can you not see sickle cell disease symptoms until after 6 months

A

HbF inhibits HbS polymerization

19
Q

Hydroxyurea

A

-increases HbF
-anti-inflammatory agent
-increases red cell volume
-produces NO

20
Q

what is the survival rate with SCD

A

90% survive to age 20 and ~50% survive past age 50

21
Q

what is the mutation in hemoglobin C disease

A

glutamate to lysine

22
Q

symptoms of Hemoglobin C disease

A

-mild hemolytic anemia
-resistance to malaria
-rare

23
Q

hemoglobin C trait

A

-HbC/HbA
-2-3% if African Americans, asymptomatic

24
Q

hemoglobin C disease

A

HbCC
0.017% have it

25
Q

HbSC disease

A

-0.08%
-can have pain crises but less severe than SS disease

26
Q

which hemoglobin resembles the washington monument

A

HbC

27
Q

Thalassemia etiology

A

-low intracellular Hb, low MCV and MCH
-dehydration and excess membrane and folding
-ineffective erythropoiesis/premature destruction of marrow erythroblasts
-hemolysis in spleen
-resistance to malaria falciparum
-mediterranean countries, africa, and se asia

28
Q

B0-thalassemia

A

absence of B globin chains

29
Q

B+-thalassemia

A

reduced B-globin chains

30
Q

what are the 3 classes of B-thalassemia mutations

A

-chain terminator B0
-promoter region B+
-splicing B+

31
Q

Beta thalassemia major

A

-rare, homozygous
-B0/B0, B0/B+, B+/B+
-anemia begins 6-9 months of age

32
Q

morphologic features of B thalassemia major

A

-decreased MCV and MCHC
-anisocytosis and poikilocytosis
-target cells, basophilic stippling, and fragmented RBCs
-relatively mild reticulocytosis

33
Q

what do target cells look like?

A

red blood cells that have a redistribution of hemoglobin, which causes a pale region to separate the redistribution. They appear as thin cups in three dimensions

34
Q

what does Beta thalassemia major look like clinically?

A

-growth retardation and decreased lifespan
-impaired bone growth
-hepatosplenomegaly
-blood transfusions help survival, anemia, and bony abnormalities
-cardiac disease from secondary hemochromatosis
-bone marrow transplantation
-prenatal diagnosis

35
Q

B thalassemia minor

A

-more common
-heterozygous (B+/B or B0/B)
-anemia is less severe, often asymptomatic
-morphologic features milder
-HbA2 and HbF elevated

36
Q

what can not be treated with iron due to overload?

A

thalassemia

37
Q

α-thalassemia

A

-impaired synthesis of α-globin chains
-decreased normal hemoglobin
-excess unpaired chains: beta, gamma, delta
-Hb Barts-newborns-Y4 tetramera
-hemolysis and ineffective erythropoiesis
-less severe than B-thalassemia

38
Q

most common mutation in α-thalassemia

A

deletion of α-globin genes

39
Q

1 α-thalassemia mutation

A

silent carrier state

40
Q

2 α-thalassemia mutations

A

-trait
-clinically similar to B-thalassemia minor
-asymptomatic
-(α/α -/-) Asian type, cis, offspring at risk for HbH disease or hydrops fetalis
-(a/- a/-) African type, trans

41
Q

3 α-thalassemia mutations

A

-HgH disease
-mostly Asian
-high affinity for O2
-HgH oxidation—->insoluble inclusions—>extravascular hemolysis
-moderately severe

42
Q

4 α-thalassemia mutations

A

-Hydrops fetalis, Hb Barts
-excess y-globulin chains
-ineffective O2 delivery
-early survival due to zeta chains that from function Hb tetramers
-fetal distress in third semester
-severe pallor, generalized edema, and massive hepatosplenomegaly
-intrauterine transfusion

43
Q

what does a CBC of a patient with HbH disease show?

A

-elevated red blood cell count
-low hematocrit
-low MCV

44
Q

how is B thalassemia diagnosed

A

-gel electrophoresis, or HPLC
-elevated Hgb A2
-HbF normal or elevated
-same CBC as alpha

45
Q

how is α-thalassemia diagnosed

A

-elevated red blood cells
-decreased MCV and MCH

Fundamentals Block 3 (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions