Molecular basis of beta-thalassemia in the population of Tunisia.
The present study attempts to delineate the spectrum of beta-thalassemia (thal) mutations in Tunisia by studying a large population from different parts of the country. A total of 285 unrelated subjects, 190 of whom had beta-thal major, 72 with Hb S/beta-thal, one with Hb C/beta-thal, one with Hb O-Arab/beta-thal and 21 beta-thal carriers, were studied. The molecular defects were detected in 97.7% of the beta-thalassemic chromosomes (n=475). Nineteen different beta-thalassemic alleles were identified. Two mutations, namely codon 39 (C-->T) and IVS-I-110 (G-->A) accounted for 70.0% of the studied chromosomes, followed by IVS-I-1 (G-->A) (4.5%). Five other mutations, frameshift codon (FSC) 44 (-C), codon 30 (G-->C), IVS-I-2 (T-->G), IVS-II-745 (C-->G), and FSC 6 (-A), are not uncommon in this population, while the remaining 11 mutations, IVS-I-5 (G-->A), -30 (T-->A), codons 25/26 (+T), IVS-I-6 (T-->C), FSC 5 (-CT), IVS-II-848 (C-->A), FSC 8 (-AA), -87 (C-->G), IVS-I-5 (G-->C), IVS-II-1 (G-->A) and IVS-II-849 (A-->C) are quite rare; four of these have not been previously reported in the Tunisian population. Potential origin and spread of these mutations to Tunisia are also discussed.
Fattoum
Slaheddine
S
Laboratoire de Biochimie et de Biologie Moleculaire, Hôpital d'Enfants, Tunis, Tunisie. slaheddine.fattoum@rns.tn
Messaoud
Taeib
T
Bibi
Amina
A
D002875:Chromosomes / Q000235:genetics*; D003062:Codon / Q000235:genetics*; D005260:Female; D016368:Frameshift Mutation / Q000235:genetics*; D005820:Genetic Testing; D005828:Genetics, Population; D006455:Hemoglobins, Abnormal / Q000235:genetics*; D006801:Humans; D008297:Male; D017354:Point Mutation / Q000235:genetics*; D011153:Population / Q000235:genetics; D014416:Tunisia; D017086:beta-Thalassemia / Q000235:genetics*
D003062:Codon; D006455:Hemoglobins, Abnormal