LEC 9 Flashcards
what is the problem with hemoglobinopathies and thalassemias
the gene that produces the globin chain has a mutation
is thalassemias qualitative or quantitative
quantitative
what types of hb are present during intrauterine
Gower-1
Gower-2
portland
Hb F
what type of Hb are present at birth
Hb F
Hb A
def? abnotmality in Hb structure and function due to a mutation in one or more globin genes
Hemoglobinopathies
what factors affect Hb function
- aa substitution
- location of globin chain
- # of genes
t or F: if someone is heterozygous (hemoglbinopathies) they will still product some Hb
T
what are the 4 most common homozygous Hemoglobinopathies
- Hb S
- HbC
- hb D
- hb E
in hb S what is glutamic acid replaced with and in what position
Val 6
what does homozygous Hb S cause
severe hemolytic anemia and sickling
in hb C what is glutamic acid replaced with and in what position
Lys 6
what does homozygous Hb C cause
mild hemolytic anemia
in hb D what is glutamic acid replaced with and in what position
Gln 121
what does homozygous Hb D cause
no anemia
in hb E what is glutamic acid replaced with and in what position
Lys 26
what does homozygous HbE cause
mild microcytic anemia
what globin chains are most likely affected in hemoglbinopathies
beta
what hb is associated with methemoglobinemia and cyanosis
Hb M
what hb is associated with increased O2 affinity
Hb Bethesda
what hb is associated with decreased O2 affinity
Hb kansas
def? hb precipitates as inclusions in RBC
Heinz bodies
what kind of thalassemias has a tetramer of normal hb chains
alpha
what type of hb is common in sub Saharan Africa, Arab India, the Americas, Eurasia, and southeast asia
Hb S
what hb has protection against malaria (p. falciparum)
Hb S (heterozygous)
t or F: when a hb S pt is oxygenated they’re blood will sickle
F
t or F: when a hb S pt is deoxygenated they’re blood will sickle
T
when O2 saturation decreases to what in a homozygous pt sickling starts
less than 85%
when O2 saturation decreases to what in a heterozygous pt sickling starts
less than 40%
what is responsible for vasoocclusive crises
reversible sickling
type of sickling: Hb S containing RBCs change shape in response to O2 tension
reversible sickling
type of sickling: cells do not change their shape regardless of O2 tension or degree of hb polymerization
irreversible sickling
at what age is Hb S noticed
6 months after birth
what virus causes an aplastic crisis (Hb S)
parvovirus B19 infection
what factors initiate vasooclusion (Hb S) (6)
- acidosis
- hypoxia
- dehydration
- infection
- fever
- extreme cold
what will the bone marrow look like of pt with Hb S
erythroid hyperplasia
def? transitional cell that will become sickle cell
oat cell
tube solubility reducing agent
sodium dithionite
what does it indicate if tube solubility test is turbid
Hb S is present