Molecular Basis of α-Thalassemia in Algeria

Abstract

An epidemiological molecular study was carried out to evaluate the spectrum and allelic frequency of α-thalassemia (α-thal) defects in Algeria. A series of 153 randomly selected blood donors was screened for 10 α-thal alleles described in the Mediterranean area. In addition, six unrelated cases with hematological and biochemical data suggestive of Hb H disease were investigated. Our data revealed an allele frequency of 4.6%. The presence of α⁰-thal determinants (−α^20.5 and – –^{MED I}) was observed both in Hb H patients and in the randomly collected samples. Overall, the −α^3.7 deletion was the most prevalent allele (2.9%), followed by the α^{Nco I}α (HBA2:c.1A>G) allele (0.6%) and by the α^{Hph I}α (HBA2:c.95 + 2_95 + 6delTGAGG), −α^20.5, – –^{MED I} alleles (0.3% each). The −α^4.2 deletion was observed in only one Hb H patient. These results outline the heterogeneity of the α-thal alleles in Algeria which reflects the anthropological history of the country. Because of their frequency, α-thal alleles are probably frequent modulators of prevalent β-globin gene-related hemoglobinopathies in Algeria.

Keywords:

• α-Thalassemia (α-thal)
• Spectrum
• Mutation
• Hb H
• Algeria