Lecture 1 - Thallasemias and Hb Probs

Question 1

thalassemias vs hemoglobinopathy:
which is due to a defect causing abnormal function of one of the globin chains?

which is due to a defect causing low quantity of the hemoglobin or chain?

Answer 1

hemoglobinopathy,

thalassemia

Question 2

hemoglobins:
Hb F is made of ____;
HbA2 is made of ___;
HbA1 is made of ____

which is most prevalent in adults?

Answer 2

Alpha2gamma2;

alpha2delta2;

alpha2beta2;

Hb A1

Question 3

alpha globin is on chromosome ____;

beta globin is on chromosome ____

Answer 3

16, 11 (along with gamma)

4 alpha globin genes

Question 4

is alpha thalassemia present before birth?

what about beta?

Answer 4

yes, no

alpha chain is in all Hb types

Question 5

cis alpha thalassemia: 2 genes deleted on (same or diff) chromosomes; seen in _____ population

Answer 5

same; asian

Question 6

trans alpha-thalassemias: 2 genes deleted on (Same or diff) chromosomes; seen in ____ population

Answer 6

different, african american

Question 7

what kind of anemia do thalassemias cause?

Answer 7

microcytic hypocrhomic

Question 8

What are Hb barts? how many gene deletions cause this?

Answer 8

Hb-gamma 4;

4

Question 9

Hb barts (don’t release/release too much) oxygen; what typically happens in these patients

Answer 9

don’t release;

die in utero (hydrops fetalis)

Question 10

another name for 3 gene deletions in alpha thalassemia? what Hb anomaly do these show?

Answer 10

Hb H disease; 4 beta globin formations

Question 11

which of the alpha thalassemias is most associated with hemolytic anemia?
what about extramedullar hematopoesis?

Answer 11

Hb H disease (ie 3 deletions);

4 gene deletions

Question 12

____ thalassemias are due to point mutations;

____ thalassemias are due to gene deletions

Answer 12

beta;

alpha

Question 13

which beta thalassemia type shows an increase in HbA2 percentage on electrophoresis?

Answer 13

minor

Question 14

why do kids with beta thalassemia major show a “Crew cut” appearance on x-ray? what characteristic facies do they show?

Answer 14

bone marrow expansion;

chipmunk

Question 15

why are children with beta thal major asympomatic until 6 months of age?

Answer 15

HbF is protective

Question 16

hepatosplenomegaly in B-thal major is due to ____

Answer 16

extramedullary hematopoeisis

Question 17

what kind of cells are seen in beta-thal?

Answer 17

target cells

Question 18

____ is the main treatment for beta-thal major. what is a possible side effect?

Answer 18

chronic transfusion;

iron overload

Question 19

amino acid change that causes sickle cell anemia?

what globin chain?

Answer 19

glutamic acid –> valine;

beta

Question 20

hemoglobins with _____ O2 affinity cause erythrocytosis

Answer 20

increased;

hold onto O2–>tissue hypoxia–>increase EPO

Question 21

methemoglobinemia is characterized by heme containing iron in the ____ state rather than the normal ____ state. is the Hb O2 affinity increased or decreased?

Answer 21

Fe3+ (ferric), Fe2+ (ferrous);

decreased

Question 22

3 conditions that precipitate sickling of RBCs?

specifically, the HbS does what?

Answer 22

low O2, high altitude, acidosis;

polymerizes

Question 23

in addition to vaso-occlusion, hemolysis of RBC’s is thought to release ____ that consumes ____ and causes a decrease in ____. this causes what?

Answer 23

arginase, arginine, NO;

vasoconstriction (and platelet activation)

Question 24

characteristic finding in kids with sickle cell anemia: _____;

what often is the cause of death in adults? what about kids?

Answer 24

dacylitis;

acute chest syndrome; infection with encapsulated organisms

Question 25

what classically causes osteomyelitis in ppl with sickle cell disease?

Answer 25

salmonella paratyphi

Question 26

what test causes sickling of cells in a test tube?

Answer 26

metabisulfite

Question 27

HbC disease is due to a mutation of _____ to ____ in ___ globin

Answer 27

glutamic acid to lysine;
beta;

think HbC and lyCine

Question 28

characteristic finding on blood smear with HbC disease?

Answer 28

hemoglobin crystals