Thalassaemic patients are indeed anaemic. Thalassaemia (or
Mediterranean Sea anaemia, which is what that Greek term means) is
a genetic condition resulting in a defect of globin chain
production. Haemoglobin, the pigment in red blood cells that
transports oxygen, is composed of haeme (which contains iron),
alpha and beta globin chains. There are 4 alleles (copies) of the
alpha globin gene and 2 of the beta globin gene. Inadequate
production of the alpha and beta globin chains results in alpha and
beta thalassaemia respectively. Depending on the degree of
abnormality, the disease varies in severity:
Alpha thalassaemia:
1 or 2 allele defect: alpha thalassaemia trait (alpha-1 and alpha-2
thalassaemia)
3 allele defect: Haemoglobin H disease (fairly severe and may
require occasional blood transfusions)
4 allele defect: Haemoglobin Bart's disease (incompatible with
life, usually stillborn)
Beta thalassaemia:
1 allele defect: beta thalassaemia minor (asymptomatic or very
mild)
2 allele defect: beta thalassaemia major (requires regular blood
transfusions and death in teenage or young adult life)
As the name implies, thalassaemia is common in the Mediterranean
Sea areas, as well as in South East Asia. However, the disease we
see in Asia tends to be more severe. Whereas thalassaemic patients
in the Mediterranean region tend to get a mutation of the globin
chain genes, we tend to get a deletion of the entire
allele(s).
As Reno said, thalassaemia confers some resistance to malaria like
sickle cell anaemia does. The red cells in these conditions are
defective and so malaria parasites tend to die within them, rather
than replicating in them. However, the flip side of it is that
haemolytic anaemia like thalassaemia may undergo massive haemolysis
in the presence of infection by Parvovirus B19.
