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Idiomas disponibles
Idiomas disponibles
I I N N T T E E R R P P R R E E T T A A T T I I O O N N O O F F R R E E S S U U L L T T S S
Q Q u u a a l l i i t t a a t t i i v v e e E E v v a a l l u u a a t t i i o o n n : :
The possible identity of the haemoglobin types present in the samples can be determined by visual
evaluation of the completed gel. The Hemo controls provide a marker for band identification.
Figure 1 shows the possible identity of the most commonly encountered haemoglobin types.
Most haemoglobin variants cause no discernible clinical symptoms, so are of interest primarily to
research scientists. Variants are clinically important when their presence leads to sickling disorders,
thalassaemia syndromes, life long cyanosis, haemolytic anaemias or erythrocytosis, or if the
heterozygote is of sufficient prevalence to warrant genetic counselling. The combinations of HbS-S,
HbS-D-Los Angeles, and HbS-O Arab lead to serious sickling disorders
HbH, E-Fort Worth and Lepore cause a thalassaemic blood picture
The two variant hemoglobins of greatest importance in terms of frequency and pathology are HbS and
2
HbC
. Sickle cell anaemia (HbSS) is a cruel and lethal disease. It first manifests itself at about 5-6
months of age. The clinical course presents agonising episodes of pain and temperature elevations with
anaemia,
listlessness,
The individual with homozygous HbCC suffers mild haemolytic anaemia which is attributed to the
precipitation or crystallization of HbC within the erythrocytes.
characterised by haemolytic anaemia that is milder than sickle-cell anaemia.
The thalassaemias are a group of haemoglobin disorders characterised by hypochromia and
microcytosis due to the diminished synthesis of one globin chain (the α or β) while synthesis of the
other chain proceeds normally
precipitate within the red cell, forming inclusion bodies that shorten the life span of the cell.
In α-thalassaemias, the α chains are diminished or absent, and in the β-thalassaemia, the β chains are
affected.
Another quantitative disorder of haemoglobin synthesis, hereditary persistent foetal
haemoglobin (HPFH), represents a genetic failure of the mechanisms that turn off gamma chain
synthesis at about four months after birth, which results in a continued high percentage of HbF. It is a
more benign condition than the true thalassaemias and persons homozygous for HPFH have normal
development, are asymptomatic and have no anemia
F
A
G
A
J
2
D
H
E
lethargy,
and
infarct
9,10
. This unbalanced synthesis results in unstable globin chains. These
O
S
C
2
.
in
virtually
10
.
4
2
. Several variants including
all
organs
of
the
Cases of HbSC disease are
body.
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