Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

3 HAEM > HAEMOGLOBINOPATHIES > Flashcards

HAEMOGLOBINOPATHIES Flashcards

(70 cards)

Start Studying
1
Q

what is the structure of HbA

A

2 alpha globin like chains
2 beta globin like chains
one haem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the structure of HbA2

A

2 alpha globin

2 delta globin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what its he structure of HbF

A

2 alpha globin

2 gamma globin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

which type of Hb is present in the greatest quantities

A

HbA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how many alpha globin producing genes are there present in each cell

A

4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

on which chromosome are the alpha globin genes located

A

chromosome 16

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how many beta globin producing genes are there in each cell

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

on which chromosome are the beta globin genes located

A

chromosome 11

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

how are the different genes for Hb production arranged on the chromosome

A

they are arranged in order of expression

eg embryonic Hb, then fetal, then adult

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the two main groups of haemoglobinopathies

A

thalassaemias

structural Hb variants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how do thalassaemias affect Hb production

A

decreased rate of normal globin chain synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how do structural Hb variants affect Hb production

A

normal production of structurally abnormal globin chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what type of anaemia does Thalassaemia cause

A

microcytic hypochromic anaemia due to inadequate Hb production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the complications of unbalanced accumulation of globin chains in Thalassaemia

A

ineffective erythropoiesis and haemolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

where are thalassaemias most commonly found geographically

A

Mediterranean coast, Southern Asia, North African coast, subsaharan Africa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

which types of Hb are affected by alpha thal

A

HbA
HbA2
HbF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the normal genotype of individuals unaffected by alpha thatl

A

(aa/aa)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how do mutations affect the genotype of patients with alpha thal

A

a+ (-a) (deletion of one alpha gene)

a0 (–) (deletion of both alpha genes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are the potential genotypes in alpha thal trait

A

one or two genes missing (out of four)
a+/a (-a/aa)
a0/a (–/aa)
a+/a+ (-a/-a)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is HbH disease (and genotype)

A

only one alpha gene is left

a0/a+ (–/-a)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is Hb Parts hydrops fetalis (and genotype)

A

no functional alpha genes

a0/a0 (–/–)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is the presentation of alpha tha trait

A

normal asymptomatic

microcytic, hypo chromic red cells with mild anaemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how can you distinguish alpha thal trait from iron deficiency anaemia

A

ferritin will be normal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

how does HbH disease present

A

anaemia with very low MCV and MCH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what are HbH molecules and why are they formed
tetramers of excess beta chains which are unable to carry oxygen produced in severe alpha that due to lack of alpha chains
26
what are clinical features of HbH disease
moderate anaemia to transfusion dependent splenomegaly due to extramdeullary haematopoiesis jaundice
27
in which populations is HbH disease most prevalent
SE asia Middle East mediterranean
28
what is the management of severe HbH disease
splenectomy +/- transfusion
29
what is the severest form of alpha thal
Hb barts hydrops fetalis
30
which types of Hb make up the majority of Hb at birth in hydrops fetalis
Hb barts (gamma tetramer) and HbH (beta tetramer)
31
why is there increased production of Hb parts and HbH in hydrops fetalis
there are no alpha genes inherited from either parent so alpha globin can't be made
32
clinical features of hydrops fetalis
``` severe anaemia cardiac failure growth retardation severe hepatosplenomegaly skeletal and cardiovascular abnormalities ```
33
which types of Hb are affected in beta thal
HbA (a2b2)
34
what is the genotype of beta thal trait
B+/B or B0/B
35
what are the clinical features of beta thal trait
asymptomatic no/mild anaemia low MCV/MCH raised HbA2
36
what is the genotype of beta thal intermedia
B+/B+ or B0/B+
37
what are the clinical features of beta thal intermedia
moderate severity anaemia
38
what is the genotype of beta thal major
B0/B0
39
at what age does beta thal major present and why
presents at 6-24 months | HbF (a2g2) levels fall and the circulation begins to depend on HbA (a2b2) which can't be produced
40
how does beta thal major present
``` pallor failure to thrive hepatosplenomegaly skeletal changes organ damage ```
41
what will Hb analysis show in beta thal major
mainly HbF | minimal HbA
42
what are complications of extramedullary haemotopiesis in beta thal major
frontal bossing | cord compression
43
how is beta thal major managed
regular transfusions to maintain Hb at 95-105 g/L
44
what is the purpose of regular transfusions in beta thal major, beyond correcting the Hb concentration
suppresses ineffective erythropoiesis | inhibits over-absorption of iron
45
what are consequences of iron overload
``` impaired growth and pubertal development diabetes osteoporosis cardiomypoathy arrhythmias cirrhosis hepatocellular cancer ```
46
how is iron overload managed in beta thal major
iron chelating drugs
47
how is iron bound to chelators excreted
in urine or stool
48
what are complications of transfusions in beta thal major
viral infection (HIV, Hep) alloantibodies transfusion reactions
49
why is there an increased risk of sepsis in an iron overloaded patient
bacteria like iron
50
what type of mutations leads to production of Bs in sickling disorders
point mutation in codon 6 of the beta globin genes that substitutes glutamine to valine
51
how is the structure of Hb altered in sickling disorders
HbA (a2B2) becomes HbS (a2Bs2)
52
how is HbS less effective than HbA
it polymerises if exposed to low oxygen levels for a prolonged period of time this distorts the red cell and damages the membrane
53
what is the genotype in sickle cell trait
one normal gene, one abnormal | B/Bs
54
what are the clinical features of sickle cell trait (HbAS)
few features are HbS levels are too low to polymerise | may sickle in severe hypoxia eg high altitude, under anaesthesia
55
what features are present on a blood film in a patient with HbAS (sickle cell trait)
normal blood film
56
what is the genotype in sickle cell anaemia (HbSS)
two abnormal genes (Bs/Bs)
57
what types of Hb are present in HbSS
>80% HbS | no HbA
58
clinical features of HbSS
episodes of tissue infarction due to vascular occlusion (sickle crisis) chronic haemolysis sequestration of sickled RBCs in liver and spleen hyposlenism due to repeated infarcts
59
where are common sites of sickle crisis
digits bone marrow lung spleen CNS
60
what is sickle cell disease cf sickle cell anaemia
presence of HbS mutation in the presence of another beta chain mutation eg HbS/beta thal
61
what are triggers for sickle crisis
``` hypoxia dehydration infection cold exposure stress/fatigue ```
62
how are painful sickle crises treated
``` opiate analgesia hydration rest oxygen antibiotics if evidence of infection red cell exchange transfusion in severe crisis (eg chest crisis or stroke) ```
63
what is red cell exchange transfusion and how does it improve symptoms in HbSS
combination of venesection followed by transfusion | decreases concentration of HbS and improves tissue perfusion
64
what are long term effects of sickle cell anaemia
impaired growth | risk of end organ damage
65
what are examples of end organ damage in sickle cell anaemia
``` pulmonary HTN renal disease avascular necrosis leg ulcers stroke ```
66
what complication does hyposplenism cause and how is it managed
increased risk of infection - prophylactic penicillin - vaccination against pneumococcus, meningococcus, haemophilia
67
long term management of sickle cell anaemia
folic acid supplementation (increased RBC turnover) hydroxycarbamide (induces HbF production) regular transfusion to prevent stroke
68
how to investigate Hbopathy
FBC (Hb, red cell indices) blood film ethnic origin high performance liquid chromatography or gel electrophoresis to quantify Hb present
69
presence of HbS is indicative of what type go Hbopathy
sickling disease
70
raised HbA2 is diagnostic of...
beta thal trait

3 HAEM (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions