Oligonucleotide Screening of β Thalassemia Mutations in the South East of France

France is a non-endemic region for β thalassemia. In this country, the sporadic cases of Cooley's disease encountered affect almost constantly subjects of Mediterranean origin. In this report, we have screened, using oligonucleotide probes, the distribution of the main β thalassemia mutations present in the population of South-eastern France whose origins lie in the mixing of several Mediterranean ethnic groups. Among 105 β thalassemia chromosomes, we have observed a limited number of alleles, since, by using oligonucleotide probes for six mutations, we have characterized the molecular defect in 90 % of the chromosomes. The four main mutations were found in more than 85 % of the chromosomes and the others in about 5 %. The distribution of the β thalassemia mutations within the various ethnic groups was determined.