α-Thalassemia haplotypes in the Algerian population

DNA mapping was performed in seven unrelated HbH patients and nine carriers for α-thalassemia trait originating from Algeria. This study has allowed us to identify four α-thalassemia haplotypes: the (−α3.7) haplotype, which is the most frequent (18 of 23 α-thalassemic chromosomes), the (−(α)20.5) haplotype, a (--) haplotype, and an (αα)T haplotype. Our results also show that the (−α3.7) haplotypes encountered in the Algerian population are heterogeneous and differ by the site of the unequal crossover responsible for the 3.7-kb deletion and the size of the interzeta fragment. In addition, during this survey we observed that normal chromosomes bearing a polymorphic BglII site are associated with different interzeta fragments.