thalassemias Flashcards
microcytic anemia are usually due to
decrease Hb
thalassemia is due to
decreased or absent production of globin chains
HbA is made of
2 alpha and 2 beta chains
HbA2 is made of
2 alpha and 2 delta chains
HbF is made of
2 alpha and 2 gamma chains
__ genes encode alpha chains
4 genes
alpha thalassemia minima
normal red cells
no sxs
carrier
alpha thalassemia minor
normal red cells
no sxs
mild anemia
alpha minor can be
cis or trans
which variant of alpha minor is more likely to affect offspring
cis
HbH for
4 beta chains
sxs of HbH disease
RBC deformity
extravascular hemolysis
HbH disease is dx by
DNA testing
treatment for HbH
transfusions
Hgb Barts is due to
no alpha chain
Hgb barts patients cannot form
HbF
Hgb barts consists of
four gamma globin chains
sxs of Hgb barts
hydrops fetalis, high output heart failure, and fetal death
beta thalassemia is due to
decreased b globin chain synthesis
__ genes encode for beta chains
two
beta thalassemia is often caused by
mutations
beta thalassemia minor will have
increased HgbA2
beta thalassemia minor is dx by
electrophoresis
beta thalassemia major begins in
first year of life
beta thalassemia major sxs
splenomegaly, ineffective erythropoiesis
4 characteristics of beta thal major
- hypo chromic, microcytic anemia
- abnormal rbc shapes
- erythroid hyperplasia
- extrameduallary hematopoiesis
what type of rbc are seen in beta thal major
target cells, basophillic stippling
target cells are due to
decreased cell vol (thalassemia) or
increased cell membrane (liver dz or splenic dysfunction)
sxs of erythroid hyperplasia
chipmunk facies
crew cut appearance
osteoporosis
extra medullary hematopoises often produces
nucleated RBCs
infection with parvovirus B19 in beta thal may cause
aplastic anemia
beta thal major will have what type of Hb presents
HbA2 or HbF
alpha and beta thal are protective against
malaria
