RESUMO
OBJECTIVES: Different thalassemia mutations have been reported in various ethnic groups and geographical regions in Tunisia. In the present study, we have investigated two rare ß(+) -thalassemia mutations, that have not previously been reported in the Tunisian population [ß -56 (G > C); HBBc. -106 G > C] and [ß -83 (G > A); HBBc. -133 G > A]. METHODS: The whole ß-globin gene was directly sequenced, and haplotype analysis was conducted through a PCR/RFLP method. RESULTS: Two new mutations were identified for the first time in Tunisia. They are located within the promoter region of ß-globin gene at position -56 (G > C) and -83 (G > A). Linkage analysis using ß-globin gene cluster haplotypes showed that these two mutations were associated with Mediterranean ß-haplotype IX [- + - + + + +] and framework 2 (FW2) [CCTCT]. CONCLUSIONS: The two newly described mutations lead to the ß(+) -thalassemia among Tunisian patients. The haplotype analysis and framework assignment have helped to identify the chromosomal background associated with these mutations, and determine their origin and spread.