This week we profile the beneficiaries of this year's appeal Six-year-old Heidi Leung Ho-yee runs around so exuberantly you wonder whether there are two of her. 'I can walk and skip at the same time!' she shouts, beaming, as she trips across her parents' tiny sitting room with walls covered in crayon. Her father, Leung Muk-po, 35, said: 'She just has to take part in all the after-school activities. She also goes swimming every day in the summer holidays.' Heidi suffers from thalassaemia major, an incurable blood disorder and one of the most common inherited conditions. Thalassaemia attacks the body's haemoglobin - a protein that gives red blood cells their characteristic red colouring and a shortage starves the body of oxygen. She will need monthly blood transfusions for the rest of her life. And five nights a week, Heidi sleeps with a needle under the skin to remove the excess iron that builds up as her haemoglobin count drops. Iron overload in the blood can lead to complications such as diabetes and heart failure. The only permanent cure is a bone marrow transplant, but this arduous process runs the risk of complications. It is also difficult to find a suitable donor. 'Thalassaemia patients require lifelong treatment, and it isn't easy,' says Dr Ha Shau-yin, who works for the Children's Thalassaemia Foundation - one of the chosen beneficiaries of the Operation Santa Claus Appeal, which will be launched in nine days' time. Formed in 1993 by medical professionals and parents of affected children, the foundation hopes to raise funds for urgently needed patient support and public awareness programmes. Up to 8.4 per cent of Hong Kong's Chinese population - one out of every 11 - are carriers of the thalassaemia gene. Carriers appear healthy, but if two carriers have a child, there is a one in four chance of the offspring having thalassaemia major. This ratio is painfully obvious in the Leung family's case - Heidi's three siblings are healthy. Dr Ha said children with thalassaemia are sometimes stillborn, or become seriously anaemic after they are born. 'Without treatment, they only live for five to 10 years.' The foundation hopes to encourage couples to take blood tests before pregnancy to see whether one or other has the gene.