Haemoglobinopathies

Question 1

Haemoglobinopathies

Answer 1

Quantitative - Thalassemias, Reduced globin chain synthesis / function
Qualitative/ Structural - Sickle cell anaemia, Mutated globin chains

Question 2

Haemoglobin

Answer 2

Haemoglobin A - 2 alpha chains, 2 beta chains
Haemoglobin A2 - 2 alpha chains, 2 delta chains
Haemoglobin F - 2 alpha chains, 2 gamma chains

Question 3

Thalassaemia syndromes

Answer 3

Disorder of globin chain synthesis
Reduction or absence of one or more chain type
Imbalance of globin chain synthesis leads to ineffective erythropoiesis and shortened red cell life span

Question 4

Structual Haemoglobinopathies

Answer 4

Characterised by synthesis of structurally abnormal globin chains
These abnormal chains can exert a wide range of effects on the behaviours of the Haemoglobin molecule

Question 5

Distrubution

Answer 5

S- most prevelant in Africa and the Caribbean, but also relatively common in Cnetral India
C - most common in West Africa partciulary Ghana
D - is most common in India, but seen in a wide range of populations
E - most common is SE Asia

Question 6

HbS

Answer 6

Point mutation in the beta chain gene, GAG to GTG
Results in subsition from glutamic acid to valine at position 6

Question 7

Sickling disorders

Answer 7

Typically sickle carrier clinically silent, rarely crises
Sickle Cell Disease includes Sickle Cell Anaemia (SS) but also combinations of Hb S with other abnormalities
Diagnosed by screening test for Hb S

Question 8

Causes of Death in Sickle Cell Anaemia

Answer 8

Infection
CVA’s
Respiratory failure

Question 9

Management

Answer 9

Hydroxyuera
Reduce number of crises