haemaglobinopathies

Question 1

list the different forms of haemoglobin and what globes chains each contains

Answer 1

HbA- 2 alpha and 2 beta
HbA2- 2 alpha and 2 delta
HbF - 2 Alph anad 2 gamma

Question 2

what chromosome is the alpha chain genes found on and b chain genes respectively

Answer 2

alpha - chromosome 16- 2 genes per chromosome -4 per cell

beta - chromosome 11- 2 genes per chromosome

Question 3

when are adult HbA levels reached by

Answer 3

6-12 months

Question 4

what type of inheritance do haemoglobinopathie have

Answer 4

autosomal recessive

Question 5

pathophysiology of thalassaemias

Answer 5

decreased rate of globin synthesis

Question 6

pathophysiology of sickle cell anaemia

Answer 6

abnormal globin chains synthesised

Question 7

what type of anaemia would be seen in thalassaemia

Answer 7

microcytic hypochromic anaemia

Question 8

how is thalassaemia diagnosed

Answer 8

high Performance Liquid chromatography

Question 9

describe the difference between A+ and A0 in alpha thalassaemia

Answer 9

A+ - deletion of 1 alpha gene

A0 -deletion of 2 alpha genes

Question 10

describe alpha thallasaemia trait

Answer 10

one or two alpha genes missing- asymptotic carrier

microcytic ans hypo chromic but ferritin normal

Question 11

describe HbH disease

Answer 11

only one Alpha gene left (–/-a)

mos to severe anaemia

Question 12

describe hb barts hyddors fetalis

Answer 12

no functional a genes - incompatible with life as alpha globin required in all haemoglobin forms

Question 13

what type of mutation causes b thallassaemia

Answer 13

point mutation

Question 14

golf ball cells

Answer 14

HbH as excessive beta chain production to make up for loss of alpha chain

Question 15

describe beta thallasaemia trait - what is diagnostic

Answer 15

missing one or 2 beta chain genes
asyp, no/mild anaemia , low MCV
raised HbA2 is diagnostic

Question 16

what is beta thalassaemia intermedia

Answer 16

either (b-/b-) or (–/b-)

Question 17

treatment of beta thallassaemia intermedia

Answer 17

occasional transfusion

Question 18

treatment of beta thalassaemia major

Answer 18

life long transfusion dependency

Question 19

what additional drug should be taken alongside transfusions in beta thalassaemia

Answer 19

iron chelating drugs eg - desferrioxamine

Question 20

what type of mutation causes sickle cell anaemia and where. what does this cause

Answer 20

point mutation in codon 6 of beta globin chain

changing of glutamine to valine

Question 21

what does extra medullary haumatopoeisis in beta thallasaemia major casuse

Answer 21

hepatosplenomegaly, skeletal changes and organ damage, cord compression

Question 22

describe sickle cell trait

Answer 22

one normal gene and one abnormal
aymptomatic and may only present in severe hypoxia eg high altitude
blood film normal mainly HbA

Question 23

describe sickle cells anaemia

Answer 23

homozygous Bs mutation
No HbA lots of HbS
episodes of tissue infarction due to occlusion as sticky RBCs

Question 24

describe how hyposplenism occurs in sickle cell anaemia

Answer 24

chronic haemolysis as shortened life span of RBC
filtered and sequestered by spleen and liver
hyposplenism due to repeated infarcts

Question 25

what can precipitate a sickle cell crisis

Answer 25

hypoxia, dehydration, cold, infection , fatigue

Question 26

long term management of sickle cell anaemia

Answer 26

penicillin if hyposplenism
folic acid - to increase RBC production
hydroxycarbamide - to induce HbF production

Question 27

what would a sickle cell crisis present with

Answer 27

pain

Question 28

treatment of sickle cell crisis

Answer 28

opiate analgesia 
oxygen 
fluids
rest
red cell change if severe

Question 29

how is sickle cell diagnosed

Answer 29

HPLC- detects HbS

Question 30

what would be seen in HPLC in beta thalassaemia

Answer 30

raised HbA2