Springer Online Journal Archives 1860-2000
Summary By using oligonucleotide hybridization, restriction endonuclease analysis and direct sequencing of amplified genomic DNA, we have been able to characterize 18 different mutations in the β-globin genes of 161 β thalassemia homozygotes and 107 β-thalassemia heterozygotes from Turkey (429 β-thalassemia chromosomes). Previous studies dealing with β-thalassemia in Mediterranean countries have shown that, in most Mediterranean populations, only a few mutations are prevalent. In contrast, β-thalassemia in Turkey does not seem to be associated with a few predominant mutations. The six most frequent alleles, IVS-I-110 (G→A), IVS-I-6(T→C), FSC-8 (-AA), IVS-I-1(G→A), -30(T→A) and FSC-5 (CT), account for only 69.3% of the disease genes; indeed, all 26 mutations assayed represent 85.8% of the disease genes, confirming the considerable molecular heterogeneity of β-thalassemia among Turks, and indicating the possible presence of rare, previously undefined, mutations in the population. Two mutations observed in this study, IVS-I-116 (T→G) and Cd44(-C), have not been reported in the Turkish population to date. Since preventive medical services, such as genetic counseling and prenatal diagnosis, are greatly improved by detailed knowledge of the molecular pathology of β thalassemia, we strongly believe that the presented data will facilitate the intended establishment of a prenatal diagnosis center, based on DNA analysis, in Turkey.
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