Molecular characterization of beta-thalassemia in north Jordan.

We have studied the beta-thalassemia mutations in 91 chromosomes of 43 patients with beta-thalassemia major and five with Hb S-beta-thalassemia, aged 6 months to 24 years. Many are blood transfusion-dependent and are being treated at the major hospital, the Princess Basma Hospital, in Irbid, Jordan. As many as 13 different mutations have been identified; three Mediterranean mutations [IVS-I-110 (G-->A), IVS-II-I (G-->A), and IVS-II-745 (C-->G)] were present in 54% of the chromosomes tested, while six other Mediterranean alleles were found in 24% of the chromosomes, for a total of 78% of Mediterranean origin. Sixteen chromosomes carried mutations which were observed in Arabian, Southeast Asian/Indian, and Iranian/Egyptian or Black populations; four beta-thalassemia mutations remained unidentified.