Thalassaemia - which is derived from the Greek word meaning sea and anaemia - is one of the most common inherited genetic blood disorders in the world. It is prevalent in Mediterranean countries, the Middle East and Asia.
The disease is caused by defective genes that affect the production of normal haemoglobin, the oxygen-carrying pigment in red blood cells. In Hong Kong, about one in 11 people is a thalassaemia-carrier, most of whom have inherited one defective gene.
Most carriers suffer mild anaemia or have no symptoms. Those who suffer from a severe form of the disorder - they would have inherited a pair of defective genes from each parent - may suffer pallor, poor appetite, enlarged liver, bone deformities and retarded growth. They need blood transfusions every four weeks.
However, the regular transfusions can result in iron overload and cause heart and liver failure. It can also lead to stunted growth, delayed puberty, diabetes and other endocrine complications.
So most patients with the severe form receive 'chelation injections', a kind of iron-removing drug, through an electrical pump at least 10 hours a night, five or six times a week.
This is a long and troublesome process for patients. Some of them may shorten the injection period at night, although this is likely to pose a threat to their life.
Bone marrow transplants offer the only option for curing the disease, but only a few thalassaemia patients are lucky enough to get access to the right type of bone marrow.