Lecture 1 - Thallasemias and Hb Probs Flashcards
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?
hemoglobinopathy,
thalassemia
hemoglobins:
Hb F is made of ____;
HbA2 is made of ___;
HbA1 is made of ____
which is most prevalent in adults?
Alpha2gamma2;
alpha2delta2;
alpha2beta2;
Hb A1
alpha globin is on chromosome ____;
beta globin is on chromosome ____
16, 11 (along with gamma)
4 alpha globin genes
is alpha thalassemia present before birth?
what about beta?
yes, no
alpha chain is in all Hb types
cis alpha thalassemia: 2 genes deleted on (same or diff) chromosomes; seen in _____ population
same; asian
trans alpha-thalassemias: 2 genes deleted on (Same or diff) chromosomes; seen in ____ population
different, african american
what kind of anemia do thalassemias cause?
microcytic hypocrhomic
What are Hb barts? how many gene deletions cause this?
Hb-gamma 4;
4
Hb barts (don’t release/release too much) oxygen; what typically happens in these patients
don’t release;
die in utero (hydrops fetalis)
another name for 3 gene deletions in alpha thalassemia? what Hb anomaly do these show?
Hb H disease; 4 beta globin formations
which of the alpha thalassemias is most associated with hemolytic anemia?
what about extramedullar hematopoesis?
Hb H disease (ie 3 deletions);
4 gene deletions
____ thalassemias are due to point mutations;
____ thalassemias are due to gene deletions
beta;
alpha
which beta thalassemia type shows an increase in HbA2 percentage on electrophoresis?
minor
why do kids with beta thalassemia major show a “Crew cut” appearance on x-ray? what characteristic facies do they show?
bone marrow expansion;
chipmunk
why are children with beta thal major asympomatic until 6 months of age?
HbF is protective
hepatosplenomegaly in B-thal major is due to ____
extramedullary hematopoeisis
what kind of cells are seen in beta-thal?
target cells
____ is the main treatment for beta-thal major. what is a possible side effect?
chronic transfusion;
iron overload
amino acid change that causes sickle cell anemia?
what globin chain?
glutamic acid –> valine;
beta
hemoglobins with _____ O2 affinity cause erythrocytosis
increased;
hold onto O2–>tissue hypoxia–>increase EPO
methemoglobinemia is characterized by heme containing iron in the ____ state rather than the normal ____ state. is the Hb O2 affinity increased or decreased?
Fe3+ (ferric), Fe2+ (ferrous);
decreased
3 conditions that precipitate sickling of RBCs?
specifically, the HbS does what?
low O2, high altitude, acidosis;
polymerizes
in addition to vaso-occlusion, hemolysis of RBC’s is thought to release ____ that consumes ____ and causes a decrease in ____. this causes what?
arginase, arginine, NO;
vasoconstriction (and platelet activation)
characteristic finding in kids with sickle cell anemia: _____;
what often is the cause of death in adults? what about kids?
dacylitis;
acute chest syndrome; infection with encapsulated organisms
what classically causes osteomyelitis in ppl with sickle cell disease?
salmonella paratyphi
what test causes sickling of cells in a test tube?
metabisulfite
HbC disease is due to a mutation of _____ to ____ in ___ globin
glutamic acid to lysine;
beta;
think HbC and lyCine
characteristic finding on blood smear with HbC disease?
hemoglobin crystals
