CHARACTERIZATION OF NONDELETION ALPHA-THALASSEMIA MUTATIONS IN THE GREEK POPULATION

Alpha-Thalassemia is usually due to deletions within the alpha-globin gene cluster, leading to loss of function of one (-alpha) or both [-(a lpha) or --] alpha-globin genes. Nondeletion mutations (denoted alphaa lpha(T) or alpha(T)alpha) are less frequent and in Greece are not well defined. We report the analysis of 16 nondeletion alpha-thalassemia c hromosomes using a polymerase chain reaction method to amplify specifi cally the alpha2-globin gene, which was subsequently screened using AS O hybridization or restriction enzyme analysis for four mutations alre ady characterized in other Mediterranean and Middle Eastern population s. Of the 16 nondeletion chromosomes, nine had the polyadenylation sig nal mutation (alpha(PolyA)alpha), two the IVSI 5' pentanucleotide dele tion (alpha(Hph)alpha), two the Hb loaria mutation (alpha(lc)alpha), a nd one the initiation codon mutation (alpha(Nco)alpha). In two, the de fects are still undefined. These findings show that nondeletion alpha- thalassemia in Greece is heterogeneous and that the most frequent muta tion (accounting for >15%) is the polyadenylation signal mutation, whi ch to date was most commonly found in the Saudi Arabian population. (C ) 1993 Wiley-Liss, Inc.