A community profile of alpha thalassaemia in Western Australia

To investigate the current prevalence of alpha-thalassaemia in the population of Western Australia, which has received substantial immigration from South-East Asia during the last 30 years.

Over a 1-year period commencing July 2002, alpha-thalassaemia DNA testing was performed on 920 blood samples received from the Migrant Health Service, referring doctors or pathology laboratories in Western Australia. Molecular testing for alpha-thalassaemia was performed on extracted DNA for single and double alpha-globin gene deletions and mutations by PCR.

An alpha-globin gene abnormality was detected in 35.4% (326/920) of samples. There were 177 cases (50.6%) with a single gene deletion alpha(+)-thalassaemia, most commonly -3.7 kb, and 102 cases (31.2%) with double alpha-gene deletions (alpha(0)-thalassaemia), including 7 cases of HbH disease.

Overall, the findings amount to 1.7 new cases of alpha-thalassaemia per 10,000 population in the 12-month period and demonstrate that alpha-thalassaemia is an increasingly common disorder in the Western Australian population. This has important implications for community outreach programmes, genetic counselling and the screening of at-risk populations.