[Molecular characterization of thalassemias in the Valencia community and its relationship with the hematological phenotype].

PURPOSE: The aim of the study is to present the first results of molecular characterization of thalassaemias in Valencian Community and their relationship with the haematological parameters. PATIENTS AND METHODS: The study includes 87 thalassemic patients: 30 alpha-thalassaemias, 40 beta-thalassaemias and 17 delta beta-thalassaemias. The molecular alterations were studied in white cell blood DNA, either following different PCR methods or by testing the digestion of the amplified PCR products with selective restriction enzymes.
RESULTS: The molecular characterization of beta-thalassaemias was achieved in 94% of the subjects, being the transition C-->T in CD-39 the most frequent (44%) of the mutations studied. 94% of the delta beta-thalassaemias studied corresponded to the delta beta-Spanish type. All the alpha thalassaemias characterized (64%) corresponded to the -alpha 3.7 deletion. The reamining 36% were negative for the alpha 0 deletions --MED, --20.5, or the non deletional mutations Hph I and NocI. DISCUSSION: In the Valencian Community, like what has been described for the beta-thalassaemias in other Mediterranean regions of Spain (Barcelona, Granada and Mallorca), a high incidence in C-->T transition in CD-39 was observed, in contrast with central and south-western regions of Spain, where the G-->A IVS-I-1 is the most frequent mutation. Our study supports that the IVS-I-6 mutations is the one with lower repercussions on the haematological parameters. Our study confirms the Spanish type of delta beta-thalassaemia as the most frequent in the Valencian Community, and that the 3.7 kb alpha deletion is the most frequent mutation for the alpha-thalassaemia, although alpha thalassaemia is also the poorly characterized form of thalassaemia.