The Inherited Diseases of Haemoglobin Are an Emerging Global Health Burden

Abstract

Thalasseamia is one of the common genetic disorders. A genetic defect causes reduction of the globin chains leading to chronic haemolytic anaemia from birth. The mainstay of treatment is blood transfusion to maintain adequate levels of the haemoglobin. Secondary iron overload in β-thalassaemia patients is secondary to multiple blood transfusions and increased iron absorption. Excesses iron potentially catalyses free-radicals generation and impairment in cellular function and integrity. Extensive iron-induced injury develops in the heart, liver, pancreas and endocrine system. In regularly transfused patients, in the absence of iron-chelation therapy, death from iron-induced heart failure occurs by the mid-teenage years. Conventional treatment with the parenteral iron chelator desferrioxamine improves mortality but it is too expensive for middle and lowincome countries. Oral iron chelators, such as deferiprone (L1) and deferasirox, appear to be promising, however, they are still too expensive or need special monitoring. Serum ferritin has been used for many years as a guide for chelation therapy. However, recent studies demonstrated that using serum ferritin or liver iron measurements as a monitor of iron-chelation intensive therapy would have been discontinued long before the iron had cleared from the heart. There is evidence of the value of myocardial T2* measurements by MRI for the detection of early cardiac iron overload which cannot be predicted by liver iron or serum ferritin and for the monitoring of iron-chelation therapy. The major problem is the expensiveness of MRI measurement. In conclusion, the problem of iron chelation in low-income countries may be summarized as follows: (i) drugs, are not available in every countries that need the medicine, (ii) the cost of drugs is too high for most low income countries, (iii) there is poor education of doctor, parents/ patients and local government about the benefit of iron chelation, (iv) there is need for monitoring of its toxicity and adverse drug reaction. In the TIF conference in Dubai, in 2006, a group of experts had agreed to send a document to the D-G of the WHO with a strong request that all chelators (currently available and those that will be available in the future) be designated essential for the treatment of transfusion dependent anaemias.