Hereditary Haematological Disorders In The Greek Population Of Cape Town

ABSTRACT

It is a recognized fact that most well defined population groups

have their own typical pattern of inherited disorders. The genetic

conditions most commonly found in Greek persons are the thalassaemias,

glucose-6-dehydrogenase (G-6-PD) deficiency and, to a lesser extent,

certain of the haemoglobinopathies. The clinical and socio-economic

consequences of these disorders are significant. In the homozygous

state, alpha-thalassaemia is incompatible with life, while thalassaemia

major (homozygous beta-thalassaemia) results in a severe anaemia with

death usually occurring in the second or third decades. Treatment to

prolong the life of these patients is very costly. Alpha- and betathalassaemia,

when heterozygous, may result in a mild anaemia or be

asymptomatic. G-6-PD deficiency results in attacks of haemolysis on

ingestion of certain medical preparations and is of far less importance

than the thalassaemias. Haemoglobin Sis the commonest haemoglobinopathy

occurring in Greeks and results in a severe clinical condition

when homozygous, as with the thalassaemias. However, the gene frequency

is far less than that of the thalassaemias.

The high prevalence of G-6-PD deficiency and haemoglobin Shave been

demonstrated to be due to the selective advantage they confer against

malaria. This same mechanism probably applies to the thalassaemias but

has not been proven. Thus, these disorders have been demonstrated to

occur more frequently in low-lying areas and places where malaria was

endemic in the past. Population movement has made this situation less

clearcut in recent times.

Cape Town has a Greek population numbering approximately 5000 persons.

As the thalassaemias, particularly, cause a notable public health

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