Molecular heterogeneity of beta-thalassemia alleles in Spain and its importance in the diagnosis and prevention of beta-thalassemia major and sickle cell disorders.

In the last 20 years, migratory flows have changed the pattern of beta-thalassemia (beta-thal) mutations in Catalonia and have also increased beta(S) prevalence, either alone or in association with beta-thal alleles. Characterization of the beta gene is needed for genetic counseling for beta-thal major and also for sickle cell diseases. The purpose of this study was to investigate the current distribution pattern of beta-thal mutations. Seventy nine individuals were characterized at the molecular level. As a first step, frequent mutations in the Mediterranean region were screened and when none of these mutations were identified, the beta-globin gene was sequenced. Screening for common mutations allowed the characterization of 60 individuals. In the remaining 19 cases, 11 different mutations were identified. beta-Thalassemia heterogeneity in Spain has markedly increased, leading to the requirement of including new methods for genetic diagnosis. Prevention of beta-thal major and sickle cell disease are necessary since their prevalence in Spain is increasing dramatically.