Springer Online Journal Archives 1860-2000
Summary We have determined the spectrum of mutations producing β-thalassemia (β-thal) in Tunisia by direct DNA analysis using hybridization with allele-specific oligonucleotide probes and restriction endonuclease assay. In all, 34 unrelated β-thal patients originating from different parts of the country were available for study. The β-globin gene cluster of each was subjected to haplotype analysis, and on the basis of this analysis, we tested each patient's DNA for one or more mutations previously shown to be linked to that haplotype. We identified four previously unreported haplotypes and found that this population differs from others in Mediterranean areas in the frequency of the β-thal haplotypes, the unexpected observation being the high frequency of haplotype IX. Six different point mutations were found, accounting for 62% of β-thal genes in this Tunisian population. The molecular defects known to be the most frequent in Mediterraneans (nonsense codon 39, IVS1 nt 110, IVS1 nt 6) only make up 37% of the mutant genes. One as yet undescribed mutation (IVS1 nt 2 T → G) was identified by molecular cloning and sequencing. Our results should help the implementation of a prenatal diagnosis program for β-thal in Tunisia.
Type of Medium: