Alpha-thalassemia in Saudi Arabia: deletion pattern.

Alpha-Thalassemia exists at a high prevalence in several regions of Saudi Arabia. The restriction endonucleases BamHI and BglII were used to investigate the molecular basis of deletion type of alpha-thalassemia in 226 subjects from the eastern and 61 subjects from the northwestern regions of the country. The arrangements -alpha/alpha alpha and -alpha/-alpha were common. BglII digestion revealed the existence of rightward deletion in a majority of the cases. Leftward deletions, both homozygous and heterozygous, were also identified. Triple alpha-gene arrangements alpha alpha alpha anti 3.7/ were observed at a low frequency in both regions.