Double heterozygote leftward/rightward deletion type alpha-thalassaemia in Saudi Arabs.

Restriction endonucleases have been used for the investigation of deletion type alpha-thalassaemias in the Saudi population. Using Bgl II digestion, we diagnosed 2 cases with 15.8- and 7.0-kb alpha-globin gene fragments. The 15.8-kb Bgl II fragment is obtained in cases with rightward deletion, while the 7.0-kb fragment occurs in cases with leftward deletion. The 2 cases reported in this paper are heterozygous leftward/rightward deletion cases. The Bam HI digestion results and haematological parameter values are reported. This is the first report of heterozygous leftward/rightward deletion in the Saudi population.