α-Thalassaemia in Tunisia: some epidemiological and molecular data

• Published in: Journal of genetics 2008-12, Vol.87 (3), p.229-234
• Main Authors: Siala, H., Ouali, F., Messaoud, T., Bibi, A., Fattoum, S.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; alpha-Thalassemia - epidemiology; alpha-Thalassemia - genetics; Animal Genetics and Genomics; Biomedical and Life Sciences; Child; Child, Preschool; Evolutionary Biology; Female; Genotype; Hemoglobin H - genetics; Humans; Iron - metabolism; Life Sciences; Male; Microbial Genetics and Genomics; Mutation - genetics; Plant Genetics and Genomics; Research Article; Tunisia - epidemiology
• ISSN: 0022-1333; 0973-7731
• DOI: 10.1007/s12041-008-0036-0

Unlike the other haemoglobinopathies, few researches have been published concerning α-thalassaemia in Tunisia. The aim of the present work is to acquire further data concerning α-thalassaemia prevalence and molecular defects spectrum in Tunisia, by collecting and studying several kinds of samples carrying α-thalassaemia. The first survey conducted on 529 cord blood samples using cellulose acetate electrophoresis, have displayed the prevalence of 7.38% Hb Bart’s carriers at birth. Molecular analyses were conducted by PCR and DNA sequencing on 20 families’ cases from the above survey carrying the Hb Bart’s at birth and on 10 Hb H diseased patients. The results showed six α-globin gene molecular defects and were responsible for α-thalassaemia: -α 3.7 , - - MedI , α TSaudi , α 2 cd23GAG→Stop , Hb Greone Hart: α 1 119CCT→TCT corresponding to 11 genotypes out of which two are responsible for Hb H disease (- - Med /-α 3.7 ) and (α TSaudi α/α TSaudi α) and a newly described polymorphism: α +6C→G . The geographical repartition of α-thal carriers showed that the -α 3.7 deletion is distributed all over the country, respectively the α HphI and α TSaudi seem to be more frequent in the central region of the northeast region. The haematological and clinical data showed a moderate phenotype with a late age of diagnosis for Hb H disease. This work had permitted, in addition to an overview on α-thalassaemia in the country, the optimization of protocols for α-thalassaemia detection in our lab, allowing further investigations concerning phenotype-genotype correlation in sickle cell disease or β-thalassaemia.