New trend in the epidemiology of thalassaemia.

Thalassaemia is the most common monogenic disorder worldwide. It is common in areas with prevalent malaria as thalassaemic red cells provide immunity against the parasite. The incidence of thalassaemia carriers is high in regions such as Mediterranean, Middle East, Indian subcontinent, Southeast Asia and South China. In the past few decades, migrants from the thalassaemia prevalent countries to non-prevalent countries, mainly North America and Central and North Europe, are rapidly increasing in number. The non-prevalent countries may not have established pre-natal screening system for thalassaemia. The genetic subtypes among the different ethnic groups vary; this may pose challenges in prenatal diagnosis. Genetic counselling on the postnatal course of thalassaemia may be affected by the genotype-phenotype correlation and coinheritance of other genetic diseases. New treatment methods improve the survival of patient with thalassaemia major, but some late complications that occur with longer survival have been recently discovered.