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
what will cause a false neg in tube solubility test
low HCT
what will cause a false pos in tube solubility test
hyperlipidemia or too much blood
what type of hb travels the fastest in gel eletrophoresis
A
what type of hb travels the 2nd fastest in gel eletrophoresis
F
t or F: gel electrophoresis will never be a STAT test
t
on alkaline electrophoresis what hb migrate with Hb S
Hb D and G
how can hb d and G further be differentiated from hb S besides alkaline electrphoresis
neg result on Hemoglobin solubility test
on alkaline electrophoresis what hb migrate with Hb C
hb A2, E, and O
what will RBCs look like in sickle cell trait
normocytic/ normochromic
sickle cell trait: hb solubility screening test results
pos
sickle cell trait: ___% Hb S and ___% HbA
40, 60
what hb is the most common non-sickling variant in US
Hb C
Hb C: hb solubility screening test results
neg
t or F: vasoocclusive crises does not occur in Hb C
T
what will RBCs look like in
normocytic / normochromic
PBS of Hb C
target cells, crystals
people with Hb E have protection against?
malaria
Hb E: Hb solubility test results
neg
Hb E: ___ MCV and ____ retic count
low and normal
what is the most common heterozygous Hb syndrome
HbSC
T or F: Hb SC may cause vasooclusion
t
PBS of hb SC:
few sickle cells and SC crystals
Hb SC solubility test results
pos
what is the problem with thalassemias
with the amount of hb
what chromosomes are involved in globin production
- and 11
how many beta genes do people have total
2
what chromosome is beta gene on
11
how many. alpha genes do people have total
4
what age is beta thalassemia diagnosis
6 months to 1 year
what age is alpha thalassemia diagnosis
fetal life
what globin chains are not produced in Beta0
beta chains
T. or F; Beta0/beta0 does not produce hbA
T
what hb will increase in Beta0
Hb F
what does it mean to be beta+
partial def of beta chains
what does it mean to be betasilent
minimal reductions in beta chain production
what does it mean to be delta beta0
no delta or beta chains are produced
if someone is homozygous (delta beta0/ delta beta0) what hb can’t they make
hb A and Hb 2a
what does it mean to be alpha +
deletion of either alpha 1 or alpha 2 globin genes
- alpha/ alpha alpha
silent
what does it mean to be alpha 0
deletion of both alpha 1 and alpha 2 globin genes.
what is the genotype of beta thalassemia minor
beta +/beta and beta 0/ beta
what is the genotype of beta thalassemia major
beta0/beta0
what is the genotype of of beta thalassemia intermedia
delta beta0 / delta beta0
what is the genotype of beta thalassemia silent carrier
b silent/ beta
what hb is elevated in beta thalassmia minor
hb A2
what is the treatment for beta thalassemia major
blood transfusion
what hb is increased in beta thalassemia major
hb F
what is seen in the pbs of beta thalassmia major
nRBCs
what condition causes bone changes
beta thalassemia major
if 1 alpha gene is present what hb is made
Hb H
if 0 alpha genes are present what hb is made
barts hb
in hb h disease what do gamma chains switch to
beta
in hb h disease what does hb h switch to
barts hb
rbc morphology of Hb h disease
hb h inclusions (golf ball)
disease? without intrauterine transfusion the fetus becomes severely anemic which leads to cardiac failure and edema in fetal subcutaneous tissues
hydrops fetalis
what type of hb is present in hydrops fetalis
barts
mentzer index =
RBC/ MCV
if mentzer index is less than 13
favors thal minor
if mentor index is more than 13
favors IDA
