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.
Laboratoire de Biochimie et de Biologie Moleculaire, Hôpital d'Enfants, Tunis, Tunisie. slaheddine.fattoum@rns.tn
Slaheddine
S
Fattoum
Taeib
T
Messaoud
Amina
A
Bibi
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