Leftward deletion alpha-thalassaemia in the Saudi Arabian population.

Restriction endonucleases Bam HI and BglII were used to investigate the molecular basis of the deletion type of alpha-thalassaemia in the Saudi population. Four homozygous cases and six heterozygous cases of the leftward deletion type of alpha-thalassaemia (-alpha) were identified. So far, the leftward type of alpha-thalassaemia has been identified mainly in the Asiatic population, while the rightward deletion is universally distributed. This paper reports for the first time the presence of leftward deletion in the Saudi population and discusses the possibility of a more universal distribution of leftward deletion.