Hemoglobinopathy and Thalassemia (Exam 3) Flashcards Preview

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Flashcards in Hemoglobinopathy and Thalassemia (Exam 3) Deck (37)
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1
Q

What is hemoglobinopathy?

A

abnormality of hemoglobin (either structure or subunits)

2
Q

What does the abnormal structure of Hb cause?

A

HbS (sickle cell anemia) | HbC | HbE

3
Q

What is the mechanism of hemoglobinopathy?

A

when Hb polypeptide is not normal

4
Q

What are the 2 things that hemoglobinopathy can be due to?

A

inherited abnormalities | genetic mutations

5
Q

What situation causes abnormal Hb to form crystals?

A

low pO2

6
Q

How can hemoglobinopathy lead to hemolytic anemia?

A

instable hemoglobin

7
Q

How many alpha alleles do we have on which chromosome?

A

4 co-dominant alpha alleles on chromosome 16

8
Q

Which alleles pair up with the alpha allele and which chromosome are they on?

A

beta, delta, and gamma (fetal) alleles on chromosome 11

9
Q

Because the beta and alpha hemoglobin alleles are on different chromosomes, what does this say about thalassemia?

A

can have both alpha thal and beta thal = better so alpha and beta are more equal in number

10
Q

What is the key important thing that the alpha and beta hemoglobins need to do in order to form a functioning normal hemoglobin?

A

pair up, equally | not equal = thalassemia

11
Q

If more alpha subunits are made than beta subunits, what type of thalassemia is this?

A

beta thalassemia

12
Q

If more beta subunits are made than alpha subunits, what type of thalassemia is this?

A

alpha thalassemia

13
Q

What is the cause of alpha thalassemia?

A

deletion of one or more alpha alleles

14
Q

What is the effect of 1, 2, 3, and 4 alpha allele deletions?

A

1 = asymptomatic normal carrier | 2 = slight anemia | 3 = severe anemia | 4 = would not make it past fetal stage

15
Q

At the beta allele locus, what 4 types of beta alleles can take the place of a normal beta allele?

A

beta-S | beta-C | beta-E | beta-Thal

16
Q

Which normal Hb is the most abundant in our circulation?

A

HbA1

17
Q

Which type of thalassemia (alpha or beta) is more common?

A

alpha

18
Q

What are the clinical manifestations of alpha thalassemia?

A

hypochromic, microcytic RBC

19
Q

What is an accumulation of beta 4 in alpha thalassemia?

A

HbH

20
Q

What is an accumulation of gamma 4 in alpha thalassemia?

A

Hb-Bart’s

21
Q

Who is a high risk for alpha thalassemia?

A

asians and blacks

22
Q

Which beta thalassemia type (major or minor) is more common?

A

minor

23
Q

What is the cause of beta thalassemia?

A

beta-Thal gene = genetic

24
Q

What is the cause of Beta Thalassemia Major?

A

homozygous recessive beta-Thal gene

25
Q

What are the 3 other names used to call Beta Thalassemia Major?

A

Cooley’s Anemia | Thalassemia Major | Homozygous Beta-Thalassemia

26
Q

What are the 8 clinical findings of Beta Thalassemia Major?

A

hypochromic, microcytic RBC | severe form hemolytic anemia = spleenomegaly | hyperplasia BM | Alpha 4 | poikilocytosis | anisocytosis | more reticulocytes | Howell-Jolly

27
Q

Who is at higher risk for Beta Thalassemia Major?

A

white people

28
Q

When can you detect symptoms for Beta Thalassemia Major in an infant and why?

A

6 months after birth | fetus only transcribes gamma alleles in utero … 6 months after birth = program switch from gamma to beta and detect for HbA1

29
Q

What is Beta Thalassemia Minor?

A

heterozygous beta thalassemia with slight anemia

30
Q

What are the 3 methods of treatment for Beta Thalassemia?

A

radiation of cells | gene therapy with viruses | stem cell therapy

31
Q

Why is gene therapy using viruses risky?

A

viruses can cause mutations

32
Q

What are the 2 methods in determining quantity?

A

Hb electrophoresis | chromatography

33
Q

What is Hb electrophoresis?

A

can determine the type and quantity based on the width of the banding

34
Q

What is chromatography?

A

rough estimate of quantity

35
Q

What are the 2 possible beta thal alleles?

A

beta-Thal0 and beta-Thal+

36
Q

What is beta-Thal0?

A

intermediate | total inactivation and no beta is produced

37
Q

What is beta-Thal+?

A

some normal but slightly less than normal