Page 111 - Essential Haematology

Chapter 7 Genetic disorders of haemoglobin / 97

2 High performance liquid chromatography A, with almost all the circulating haemoglobin
(HPLC) is now usually used as first - line method being Hb F. The Hb A 2 percentage is normal,

to diagnose haemoglobin disorders (Fig. 7.12 b). low or slightly raised (Fig. 7.12 a). DNA
HPLC or haemoglobin electrophoresis reveals analysis is used to identify the defect on each
absence or almost complete absence of Hb allele.

Disease Origin A 2 S F A H
Normal
(or αthal trait)

Sickle cell trait

Sickle cell disease

β-thalassaemia
trait
0
β -thalassaemia
major
Sickle cell/
0
β -thalassaemia
C S F
Sickle cell/Hb C
disease
Haemoglobin
H disease
(a)
F A A 2 S
45

Haemoglobin (%) 30

15

0

0 1 2 3 4 5 6
Time (min)
(b)

Figure 7.12 (a) Haemoglobin electrophoretic patterns in normal adult human blood and in subjects with sickle

cell (Hb S) trait or disease, β - thalassaemia trait, β - thalassaemia major, Hb S/ β - thalassaemia or Hb S/Hb C

disease and Hb H disease. (b) High performance liquid chromatography. The different haemoglobins elute at
different times from the column and their concentrations are read automatically. In this example, the patient is a
carrier of sickle cell disease.